Indirect storage of data in a dispersed storage system

ABSTRACT

A method begins by a dispersed storage processing module obtaining data for storage. The method continues with the dispersed storage processing module encoding the data in accordance with an error coding dispersal storage function to produce a plurality of sets of encoded data slices. The method continues with the dispersed storage processing module determining a proxy unit. The method continues with the dispersed storage processing module transmitting the plurality of sets of encoded data slices to the proxy unit, wherein the proxy unit disperses the plurality of sets of encoded data slices to a plurality of dispersed storage units.

CROSS REFERENCE TO RELATED PATENTS

This patent application is claiming priority under 35 USC §119(e) to aprovisionally filed patent application entitled AUTONOMOUS DISTRIBUTEDSTORAGE NETWORK, having a provisional filing date of Oct. 30, 2009, anda provisional Ser. No. 61/256,314.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

NOT APPLICABLE

INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC

NOT APPLICABLE

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

This invention relates generally to computing systems and moreparticularly to data storage solutions within such computing systems.

2. Description of Related Art

Computers are known to communicate, process, and store data. Suchcomputers range from wireless smart phones to data centers that supportmillions of web searches, stock trades, or on-line purchases every day.In general, a computing system generates data and/or manipulates datafrom one form into another. For instance, an image sensor of thecomputing system generates raw picture data and, using an imagecompression program (e.g., JPEG, MPEG, etc.), the computing systemmanipulates the raw picture data into a standardized compressed image.

With continued advances in processing speed and communication speed,computers are capable of processing real time multimedia data forapplications ranging from simple voice communications to streaming highdefinition video. As such, general-purpose information appliances arereplacing purpose-built communications devices (e.g., a telephone). Forexample, smart phones can support telephony communications but they arealso capable of text messaging and accessing the internet to performfunctions including email, web browsing, remote applications access, andmedia communications (e.g., telephony voice, image transfer, musicfiles, video files, real time video streaming. etc.).

Each type of computer is constructed and operates in accordance with oneor more communication, processing, and storage standards. As a result ofstandardization and with advances in technology, more and moreinformation content is being converted into digital formats. Forexample, more digital cameras are now being sold than film cameras, thusproducing more digital pictures. As another example, web-basedprogramming is becoming an alternative to over the air televisionbroadcasts and/or cable broadcasts. As further examples, papers, books,video entertainment, home video, etc. are now being stored digitally,which increases the demand on the storage function of computers.

A typical computer storage system includes one or more memory devicesaligned with the needs of the various operational aspects of thecomputer's processing and communication functions. Generally, theimmediacy of access dictates what type of memory device is used. Forexample, random access memory (RAM) memory can be accessed in any randomorder with a constant response time, thus it is typically used for cachememory and main memory. By contrast, memory device technologies thatrequire physical movement such as magnetic disks, tapes, and opticaldiscs, have a variable response time as the physical movement can takelonger than the data transfer, thus they are typically used forsecondary memory (e.g., hard drive, backup memory, etc.).

A computer's storage system will be compliant with one or more computerstorage standards that include, but are not limited to, network filesystem (NFS), flash file system (FFS), disk file system (DFS), smallcomputer system interface (SCSI), internet small computer systeminterface (iSCSI), file transfer protocol (FTP), and web-baseddistributed authoring and versioning (WebDAV). These standards specifythe data storage format (e.g., files, data objects, data blocks,directories, etc.) and interfacing between the computer's processingfunction and its storage system, which is a primary function of thecomputer's memory controller.

Despite the standardization of the computer and its storage system,memory devices fail; especially commercial grade memory devices thatutilize technologies incorporating physical movement (e.g., a discdrive). For example, it is fairly common for a disc drive to routinelysuffer from bit level corruption and to completely fail after threeyears of use. One solution is to use a higher-grade disc drive, whichadds significant cost to a computer.

Another solution is to utilize multiple levels of redundant disc drivesto replicate the data into two or more copies. One such redundant driveapproach is called redundant array of independent discs (RAID). In aRAID device, a RAID controller adds parity data to the original databefore storing it across the array. The parity data is calculated fromthe original data such that the failure of a disc will not result in theloss of the original data. For example, RAID 5 uses three discs toprotect data from the failure of a single disc. The parity data, andassociated redundancy overhead data, reduces the storage capacity ofthree independent discs by one third (e.g., n−1=capacity). RAID 6 canrecover from a loss of two discs and requires a minimum of four discswith a storage capacity of n−2.

While RAID addresses the memory device failure issue, it is not withoutits own failures issues that affect its effectiveness, efficiency andsecurity. For instance, as more discs are added to the array, theprobability of a disc failure increases, which increases the demand formaintenance. For example, when a disc fails, it needs to be manuallyreplaced before another disc fails and the data stored in the RAIDdevice is lost. To reduce the risk of data loss, data on a RAID deviceis typically copied on to one or more other RAID devices. While thisaddresses the loss of data issue, it raises a security issue sincemultiple copies of data are available, which increases the chances ofunauthorized access. Further, as the amount of data being stored grows,the overhead of RAID devices becomes a non-trivial efficiency issue.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

FIG. 1 is a schematic block diagram of an embodiment of a computingsystem in accordance with the invention;

FIG. 2 is a schematic block diagram of an embodiment of a computing corein accordance with the invention;

FIG. 3 is a schematic block diagram of an embodiment of a distributedstorage processing unit in accordance with the invention;

FIG. 4 is a schematic block diagram of an embodiment of a grid module inaccordance with the invention;

FIG. 5 is a diagram of an example embodiment of error coded data slicecreation in accordance with the invention;

FIG. 6 is a flowchart illustrating an example of storing slices inaccordance with the present invention;

FIG. 7 is a flowchart illustrating an example of a response to asolicitation to store slices in accordance with the present invention;

FIG. 8 is a flowchart illustrating an example of retrieving slices inaccordance with the present invention;

FIG. 9 is a flowchart illustrating an example of a response to asolicitation to retrieve slices in accordance with the presentinvention;

FIG. 10 is another flowchart illustrating another example of storingslices in accordance with the present invention;

FIG. 11 is another flowchart illustrating another example of storingslices in accordance with the present invention;

FIG. 12 is another flowchart illustrating another example of retrievingslices in accordance with the present invention;

FIG. 13 is another flowchart illustrating another example of retrievingslices in accordance with the present invention;

FIG. 14 is another flowchart illustrating another example of storingslices in accordance with the present invention;

FIG. 15 is another flowchart illustrating another example of retrievingslices in accordance with the present invention;

FIG. 16 is a schematic block diagram of an embodiment of a socialtelevision media storage system in accordance with the invention;

FIG. 17 is a schematic block diagram of an embodiment of a distributedstorage system utilizing a routing storage layer in accordance with theinvention;

FIG. 18 is an example table representing a routing table in accordancewith the present invention;

FIG. 19 is a flowchart illustrating an example of determining routers inaccordance with the present invention;

FIG. 20 is a flowchart illustrating an example of affiliating routers inaccordance with the present invention; and

FIG. 21 is a flowchart illustrating an example of routing data inaccordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a schematic block diagram of a computing system 10 thatincludes one or more of a first type of user devices 12, one or more ofa second type of user devices 14, at least one distributed storage (DS)processing unit 16, at least one DS managing unit 18, at least onestorage integrity processing unit 20, and a distributed storage network(DSN) memory 22 coupled via a network 24. The network 24 may include oneor more wireless and/or wire lined communication systems; one or moreprivate intranet systems and/or public internet systems; and/or one ormore local area networks (LAN) and/or wide area networks (WAN).

The DSN memory 22 includes a plurality of distributed storage (DS) units36 for storing data of the system. Each of the DS units 36 includes aprocessing module and memory and may be located at a geographicallydifferent site than the other DS units (e.g., one in Chicago, one inMilwaukee, etc.). The processing module may be a single processingdevice or a plurality of processing devices. Such a processing devicemay be a microprocessor, micro-controller, digital signal processor,microcomputer, central processing unit, field programmable gate array,programmable logic device, state machine, logic circuitry, analogcircuitry, digital circuitry, and/or any device that manipulates signals(analog and/or digital) based on hard coding of the circuitry and/oroperational instructions. The processing module may have an associatedmemory and/or memory element, which may be a single memory device, aplurality of memory devices, and/or embedded circuitry of the processingmodule. Such a memory device may be a read-only memory, random accessmemory, volatile memory, non-volatile memory, static memory, dynamicmemory, flash memory, cache memory, and/or any device that storesdigital information. Note that if the processing module includes morethan one processing device, the processing devices may be centrallylocated (e.g., directly coupled together via a wired and/or wireless busstructure) or may be distributedly located (e.g., cloud computing viaindirect coupling via a local area network and/or a wide area network).Further note that when the processing module implements one or more ofits functions via a state machine, analog circuitry, digital circuitry,and/or logic circuitry, the memory and/or memory element storing thecorresponding operational instructions may be embedded within, orexternal to, the circuitry comprising the state machine, analogcircuitry, digital circuitry, and/or logic circuitry. Still further notethat, the memory element stores, and the processing module executes,hard coded and/or operational instructions corresponding to at leastsome of the steps and/or functions illustrated in FIGS. 1-21.

Each of the user devices 12-14, the DS processing unit 16, the DSmanaging unit 18, and the storage integrity processing unit 20 may be aportable computing device (e.g., a social networking device, a gamingdevice, a cell phone, a smart phone, a personal digital assistant, adigital music player, a digital video player, a laptop computer, ahandheld computer, a video game controller, and/or any other portabledevice that includes a computing core) and/or a fixed computing device(e.g., a personal computer, a computer server, a cable set-top box, asatellite receiver, a television set, a printer, a fax machine, homeentertainment equipment, a video game console, and/or any type of homeor office computing equipment). Such a portable or fixed computingdevice includes a computing core 26 and one or more interfaces 30, 32,and/or 33. An embodiment of the computing core 26 will be described withreference to FIG. 2.

With respect to the interfaces, each of the interfaces 30, 32, and 33includes software and/or hardware to support one or more communicationlinks via the network 24 and/or directly. For example, interfaces 30support a communication link (wired, wireless, direct, via a LAN, viathe network 24, etc.) between the first type of user device 14 and theDS processing unit 16. As another example, DSN interface 32 supports aplurality of communication links via the network 24 between the DSNmemory 22 and the DS processing unit 16, the first type of user device12, and/or the storage integrity processing unit 20. As yet anotherexample, interface 33 supports a communication link between the DSmanaging unit 18 and any one of the other devices and/or units 12, 14,16, 20, and/or 22 via the network 24.

In general and with respect to data storage, the system 10 supportsthree primary functions: distributed network data storage management,distributed data storage and retrieval, and data storage integrityverification. In accordance with these three primary functions, data canbe distributedly stored in a plurality of physically different locationsand subsequently retrieved in a reliable and secure manner regardless offailures of individual storage devices, failures of network equipment,the duration of storage, the amount of data being stored, attempts athacking the data, etc.

The DS managing unit 18 performs distributed network data storagemanagement functions, which include establishing distributed datastorage parameters, performing network operations, performing networkadministration, and/or performing network maintenance. The DS managingunit 18 establishes the distributed data storage parameters (e.g.,allocation of virtual DSN memory space, distributed storage parameters,security parameters, billing information, user profile information,etc.) for one or more of the user devices 12-14 (e.g., established forindividual devices, established for a user group of devices, establishedfor public access by the user devices, etc.). For example, the DSmanaging unit 18 coordinates the creation of a vault (e.g., a virtualmemory block) within the DSN memory 22 for a user device (for a group ofdevices, or for public access). The DS managing unit 18 also determinesthe distributed data storage parameters for the vault. In particular,the DS managing unit 18 determines a number of slices (e.g., the numberthat a data segment of a data file and/or data block is partitioned intofor distributed storage) and a read threshold value (e.g., the minimumnumber of slices required to reconstruct the data segment).

As another example, the DS managing module 18 creates and stores,locally or within the DSN memory 22, user profile information. The userprofile information includes one or more of authentication information,permissions, and/or the security parameters. The security parameters mayinclude one or more of encryption/decryption scheme, one or moreencryption keys, key generation scheme, and data encoding/decodingscheme.

As yet another example, the DS managing unit 18 creates billinginformation for a particular user, user group, vault access, publicvault access, etc. For instance, the DS managing unit 18 tracks thenumber of times a user accesses a private vault and/or public vaults,which can be used to generate a per-access bill. In another instance,the DS managing unit 18 tracks the amount of data stored and/orretrieved by a user device and/or a user group, which can be used togenerate a per-data-amount bill.

The DS managing unit 18 also performs network operations, networkadministration, and/or network maintenance. As at least part ofperforming the network operations and/or administration, the DS managingunit 18 monitors performance of the devices and/or units of the system10 for potential failures, determines the devices and/or unit'sactivation status, determines the devices' and/or units' loading, andany other system level operation that affects the performance level ofthe system 10. For example, the DS managing unit 18 receives andaggregates network management alarms, alerts, errors, statusinformation, performance information, and messages from the devices12-14 and/or the units 16, 20, 36. For example, the DS managing unit 18receives a simple network management protocol (SNMP) message regardingthe status of the DS processing unit 16.

The DS managing unit 18 performs the network maintenance by identifyingequipment within the system 10 that needs replacing, upgrading,repairing, and/or expanding. For example, the DS managing unit 18determines that the DSN memory 22 needs more DS units 36 or that one ormore of the DS units 36 needs updating.

The second primary function (i.e., distributed data storage andretrieval) begins and ends with a user device 12-14. For instance, if asecond type of user device 14 has a data file 38 and/or data block 40 tostore in the DSN memory 22, it sends the data file 38 and/or data block40 to the DS processing unit 16 via its interface 30. As will bedescribed in greater detail with reference to FIG. 2, the interface 30functions to mimic a conventional operating system (OS) file systeminterface (e.g., network file system (NFS), flash file system (FFS),disk file system (DFS), file transfer protocol (FTP), web-baseddistributed authoring and versioning (WebDAV), etc.) and/or a blockmemory interface (e.g., small computer system interface (SCSI), internetsmall computer system interface (iSCSI), etc.). In addition, theinterface 30 may attach a user identification code (ID) to the data file38 and/or data block 40.

The DS processing unit 16 receives the data file 38 and/or data block 40via its interface 30 and performs a distributed storage (DS) process 34thereon (e.g., an error coding dispersal storage function). The DSprocessing 34 begins by partitioning the data file 38 and/or data block40 into one or more data segments, which is represented as Y datasegments. For example, the DS processing 34 may partition the data file38 and/or data block 40 into a fixed byte size segment (e.g., 2¹ to2^(n) bytes, where n=>2) or a variable byte size (e.g., change byte sizefrom segment to segment, or from groups of segments to groups ofsegments, etc.).

For each of the Y data segments, the DS processing 34 error encodes(e.g., forward error correction (FEC), information dispersal algorithm,or error correction coding) and slices (or slices then error encodes)the data segment into a plurality of error coded (EC) data slices 42-48,which is represented as X slices per data segment. The number of slices(X) per segment, which corresponds to a number of pillars n, is set inaccordance with the distributed data storage parameters and the errorcoding scheme. For example, if a Reed-Solomon (or other FEC scheme) isused in an n/k system, then a data segment is divided into n slices,where k number of slices is needed to reconstruct the original data(i.e., k is the threshold). As a few specific examples, the n/k factormay be 5/3; 6/4; 8/6; 8/5; 16/10.

For each slice 42-48, the DS processing unit 16 creates a unique slicename and appends it to the corresponding slice 42-48. The slice nameincludes universal DSN memory addressing routing information (e.g.,virtual memory addresses in the DSN memory 22) and user-specificinformation (e.g., user ID, file name, data block identifier, etc.).

The DS processing unit 16 transmits the plurality of EC slices 42-48 toa plurality of DS units 36 of the DSN memory 22 via the DSN interface 32and the network 24. The DSN interface 32 formats each of the slices fortransmission via the network 24. For example, the DSN interface 32 mayutilize an internet protocol (e.g., TCP/IP, etc.) to packetize theslices 42-48 for transmission via the network 24.

The number of DS units 36 receiving the slices 42-48 is dependent on thedistributed data storage parameters established by the DS managing unit18. For example, the DS managing unit 18 may indicate that each slice isto be stored in a different DS unit 36. As another example, the DSmanaging unit 18 may indicate that like slice numbers of different datasegments are to be stored in the same DS unit 36. For example, the firstslice of each of the data segments is to be stored in a first DS unit36, the second slice of each of the data segments is to be stored in asecond DS unit 36, etc. In this manner, the data is encoded anddistributedly stored at physically diverse locations to improved datastorage integrity and security. Further examples of encoding the datasegments will be provided with reference to one or more of FIGS. 2-21.

Each DS unit 36 that receives a slice 42-48 for storage translates thevirtual DSN memory address of the slice into a local physical addressfor storage. Accordingly, each DS unit 36 maintains a virtual tophysical memory mapping to assist in the storage and retrieval of data.

The first type of user device 12 performs a similar function to storedata in the DSN memory 22 with the exception that it includes the DSprocessing 34. As such, the device 12 encodes and slices the data fileand/or data block it has to store. The device then transmits the slices11 to the DSN memory via its DSN interface 32 and the network 24.

For a second type of user device 14 to retrieve a data file or datablock from memory, it issues a read command via its interface 30 to theDS processing unit 16. The DS processing unit 16 performs the DSprocessing 34 to identify the DS units 36 storing the slices of the datafile and/or data block based on the read command. The DS processing unit16 may also communicate with the DS managing unit 18 to verify that theuser device 14 is authorized to access the requested data.

Assuming that the user device is authorized to access the requesteddata, the DS processing unit 16 issues slice read commands to at least athreshold number of the DS units 36 storing the requested data (e.g., toat least 10 DS units for a 16/10 error coding scheme). Each of the DSunits 36 receiving the slice read command, verifies the command,accesses its virtual to physical memory mapping, retrieves the requestedslice, or slices, and transmits it to the DS processing unit 16.

Once the DS processing unit 16 has received a read threshold number ofslices for a data segment, it performs an error decoding function andde-slicing to reconstruct the data segment. When Y number of datasegments has been reconstructed, the DS processing unit 16 provides thedata file 38 and/or data block 40 to the user device 14. Note that thefirst type of user device 12 performs a similar process to retrieve adata file and/or data block.

The storage integrity processing unit 20 performs the third primaryfunction of data storage integrity verification. In general, the storageintegrity processing unit 20 periodically retrieves slices 45, and/orslice names, of a data file or data block of a user device to verifythat one or more slices have not been corrupted or lost (e.g., the DSunit failed). The retrieval process mimics the read process previouslydescribed.

If the storage integrity processing unit 20 determines that one or moreslices is corrupted or lost, it rebuilds the corrupted or lost slice(s)in accordance with the error coding scheme. The storage integrityprocessing unit 20 stores the rebuild slice, or slices, in theappropriate DS unit(s) 36 in a manner that mimics the write processpreviously described.

FIG. 2 is a schematic block diagram of an embodiment of a computing core26 that includes a processing module 50, a memory controller 52, mainmemory 54, a video graphics processing unit 55, an input/output (TO)controller 56, a peripheral component interconnect (PCI) interface 58,at least one IO device interface module 62, a read only memory (ROM)basic input output system (BIOS) 64, and one or more memory interfacemodules. The memory interface module(s) includes one or more of auniversal serial bus (USB) interface module 66, a host bus adapter (HBA)interface module 68, a network interface module 70, a flash interfacemodule 72, a hard drive interface module 74, and a DSN interface module76. Note the DSN interface module 76 and/or the network interface module70 may function as the interface 30 of the user device 14 of FIG. 1.Further note that the IO device interface module 62 and/or the memoryinterface modules may be collectively or individually referred to as IOports.

The processing module 50 may be a single processing device or aplurality of processing devices. Such a processing device may be amicroprocessor, micro-controller, digital signal processor,microcomputer, central processing unit, field programmable gate array,programmable logic device, state machine, logic circuitry, analogcircuitry, digital circuitry, and/or any device that manipulates signals(analog and/or digital) based on hard coding of the circuitry and/oroperational instructions. The processing module 50 may have anassociated memory and/or memory element, which may be a single memorydevice, a plurality of memory devices, and/or embedded circuitry of theprocessing module 50. Such a memory device may be a read-only memory,random access memory, volatile memory, non-volatile memory, staticmemory, dynamic memory, flash memory, cache memory, and/or any devicethat stores digital information. Note that if the processing module 50includes more than one processing device, the processing devices may becentrally located (e.g., directly coupled together via a wired and/orwireless bus structure) or may be distributedly located (e.g., cloudcomputing via indirect coupling via a local area network and/or a widearea network). Further note that when the processing module 50implements one or more of its functions via a state machine, analogcircuitry, digital circuitry, and/or logic circuitry, the memory and/ormemory element storing the corresponding operational instructions may beembedded within, or external to, the circuitry comprising the statemachine, analog circuitry, digital circuitry, and/or logic circuitry.Still further note that, the memory element stores, and the processingmodule 50 executes, hard coded and/or operational instructionscorresponding to at least some of the steps and/or functions illustratedin FIGS. 1-21.

FIG. 3 is a schematic block diagram of an embodiment of a dispersedstorage (DS) processing module 34 of user device 12 and/or of the DSprocessing unit 16. The DS processing module 34 includes a gatewaymodule 78, an access module 80, a grid module 82, and a storage module84. The DS processing module 34 may also include an interface 30 and theDSnet interface 32 or the interfaces 68 and/or 70 may be part of user 12or of the DS processing unit 14. The DS processing module 34 may furtherinclude a bypass/feedback path between the storage module 84 to thegateway module 78. Note that the modules 78-84 of the DS processingmodule 34 may be in a single unit or distributed across multiple units.

In an example of storing data, the gateway module 78 receives anincoming data object that includes a user ID field 86, an object namefield 88, and the data object field 40 and may also receivecorresponding information that includes a process identifier (e.g., aninternal process/application ID), metadata, a file system directory, ablock number, a transaction message, a user device identity (ID), a dataobject identifier, a source name, and/or user information. The gatewaymodule 78 authenticates the user associated with the data object byverifying the user ID 86 with the managing unit 18 and/or anotherauthenticating unit.

When the user is authenticated, the gateway module 78 obtains userinformation from the management unit 18, the user device, and/or theother authenticating unit. The user information includes a vaultidentifier, operational parameters, and user attributes (e.g., userdata, billing information, etc.). A vault identifier identifies a vault,which is a virtual memory space that maps to a set of DS storage units36. For example, vault 1 (i.e., user 1's DSN memory space) includeseight DS storage units (X=8 wide) and vault 2 (i.e., user 2's DSN memoryspace) includes sixteen DS storage units (X=16 wide). The operationalparameters may include an error coding algorithm, the width n (number ofpillars X or slices per segment for this vault), a read threshold T, awrite threshold, an encryption algorithm, a slicing parameter, acompression algorithm, an integrity check method, caching settings,parallelism settings, and/or other parameters that may be used to accessthe DSN memory layer.

The gateway module 78 uses the user information to assign a source name35 to the data. For instance, the gateway module 60 determines thesource name 35 of the data object 40 based on the vault identifier andthe data object. For example, the source name may contain a fileidentifier (ID), a vault generation number, a reserved field, and avault identifier (ID). As another example, the gateway module 78 maygenerate the file ID based on a hash function of the data object 40.Note that the gateway module 78 may also perform message conversion,protocol conversion, electrical conversion, optical conversion, accesscontrol, user identification, user information retrieval, trafficmonitoring, statistics generation, configuration, management, and/orsource name determination.

The access module 80 receives the data object 40 and creates a series ofdata segments 1 through Y 90-92 in accordance with a data storageprotocol (e.g., file storage system, a block storage system, and/or anaggregated block storage system). The number of segments Y may be chosenor randomly assigned based on a selected segment size and the size ofthe data object. For example, if the number of segments is chosen to bea fixed number, then the size of the segments varies as a function ofthe size of the data object. For instance, if the data object is animage file of 4,194,304 eight bit bytes (e.g., 33,554,432 bits) and thenumber of segments Y=131,072, then each segment is 256 bits or 32 bytes.As another example, if segment sized is fixed, then the number ofsegments Y varies based on the size of data object. For instance, if thedata object is an image file of 4,194,304 bytes and the fixed size ofeach segment is 4,096 bytes, the then number of segments Y=1,024. Notethat each segment is associated with the same source name.

The grid module 82 receives the data segments and may manipulate (e.g.,compression, encryption, cyclic redundancy check (CRC), etc.) each ofthe data segments before performing an error coding function of theerror coding dispersal storage function to produce a pre-manipulateddata segment. After manipulating a data segment, if applicable, the gridmodule 82 error encodes (e.g., Reed-Solomon, Convolution encoding,Trellis encoding, etc.) the data segment or manipulated data segmentinto X error coded data slices 42-44.

The value X, or the number of pillars (e.g., X=16), is chosen as aparameter of the error coding dispersal storage function. Otherparameters of the error coding dispersal function include a readthreshold T, a write threshold W, etc. The read threshold (e.g., T=10,when X=16) corresponds to the minimum number of error-free error codeddata slices required to reconstruct the data segment. In other words,the DS processing module 34 can compensate for X-T (e.g., 16−10=6)missing error coded data slices per data segment. The write threshold Wcorresponds to a minimum number of DS storage units that acknowledgeproper storage of their respective data slices before the DS processingmodule indicates proper storage of the encoded data segment. Note thatthe write threshold is greater than or equal to the read threshold for agiven number of pillars (X).

For each data slice of a data segment, the grid module 82 generates aunique slice name 37 and attaches it thereto. The slice name 37 includesa universal routing information field and a vault specific field and maybe 48 bytes (e.g., 24 bytes for each of the universal routinginformation field and the vault specific field). As illustrated, theuniversal routing information field includes a slice index, a vault ID,a vault generation, and a reserved field. The slice index is based onthe pillar number and the vault ID and, as such, is unique for eachpillar (e.g., slices of the same pillar for the same vault for anysegment will share the same slice index). The vault specific fieldincludes a data name, which includes a file ID and a segment number(e.g., a sequential numbering of data segments 1-Y of a simple dataobject or a data block number).

Prior to outputting the error coded data slices of a data segment, thegrid module may perform post-slice manipulation on the slices. Ifenabled, the manipulation includes slice level compression, encryption,CRC, addressing, tagging, and/or other manipulation to improve theeffectiveness of the computing system.

When the error coded data slices of a data segment are ready to beoutputted, the grid module 82 determines which of the DS storage units36 will store the EC data slices based on a dispersed storage memorymapping associated with the user's vault and/or DS storage unitattributes. The DS storage unit attributes may include availability,self-selection, performance history, link speed, link latency,ownership, available DSN memory, domain, cost, a prioritization scheme,a centralized selection message from another source, a lookup table,data ownership, and/or any other factor to optimize the operation of thecomputing system. Note that the number of DS storage units 36 is equalto or greater than the number of pillars (e.g., X) so that no more thanone error coded data slice of the same data segment is stored on thesame DS storage unit 36. Further note that EC data slices of the samepillar number but of different segments (e.g., EC data slice 1 of datasegment 1 and EC data slice 1 of data segment 2) may be stored on thesame or different DS storage units 36.

The storage module 84 performs an integrity check on the outboundencoded data slices and, when successful, identifies a plurality of DSstorage units based on information provided by the grid module 82. Thestorage module 84 then outputs the encoded data slices 1 through X ofeach segment 1 through Y to the DS storage units 36. Each of the DSstorage units 36 stores its EC data slice(s) and maintains a localvirtual DSN address to physical location table to convert the virtualDSN address of the EC data slice(s) into physical storage addresses.

In an example of a read operation, the user device 12 and/or 14 sends aread request to the DS processing unit 14, which authenticates therequest. When the request is authentic, the DS processing unit 14 sendsa read message to each of the DS storage units 36 storing slices of thedata object being read. The slices are received via the DSnet interface32 and processed by the storage module 84, which performs a parity checkand provides the slices to the grid module 82 when the parity check wassuccessful. The grid module 82 decodes the slices in accordance with theerror coding dispersal storage function to reconstruct the data segment.The access module 80 reconstructs the data object from the data segmentsand the gateway module 78 formats the data object for transmission tothe user device.

FIG. 4 is a schematic block diagram of an embodiment of a grid module 82that includes a control unit 73, a pre-slice manipulator 75, an encoder77, a slicer 79, a post-slice manipulator 81, a pre-slice de-manipulator83, a decoder 85, a de-slicer 87, and/or a post-slice de-manipulator 89.Note that the control unit 73 may be partially or completely external tothe grid module 82. For example, the control unit 73 may be part of thecomputing core at a remote location, part of a user device, part of theDS managing unit 18, or distributed amongst one or more DS storageunits.

In an example of write operation, the pre-slice manipulator 75 receivesa data segment 90-92 and a write instruction from an authorized userdevice. The pre-slice manipulator 75 determines if pre-manipulation ofthe data segment 90-92 is required and, if so, what type. The pre-slicemanipulator 75 may make the determination independently or based oninstructions from the control unit 73, where the determination is basedon a computing system-wide predetermination, a table lookup, vaultparameters associated with the user identification, the type of data,security requirements, available DSN memory, performance requirements,and/or other metadata.

Once a positive determination is made, the pre-slice manipulator 75manipulates the data segment 90-92 in accordance with the type ofmanipulation. For example, the type of manipulation may be compression(e.g., Lempel-Ziv-Welch, Huffman, Golomb, fractal, wavelet, etc.),signatures (e.g., Digital Signature Algorithm (DSA), Elliptic Curve DSA,Secure Hash Algorithm, etc.), watermarking, tagging, encryption (e.g.,Data Encryption Standard, Advanced Encryption Standard, etc.), addingmetadata (e.g., time/date stamping, user information, file type, etc.),cyclic redundancy check (e.g., CRC32), and/or other data manipulationsto produce the pre-manipulated data segment.

The encoder 77 encodes the pre-manipulated data segment 92 using aforward error correction (FEC) encoder (and/or other type of erasurecoding and/or error coding) to produce an encoded data segment 94. Theencoder 77 determines which forward error correction algorithm to usebased on a predetermination associated with the user's vault, a timebased algorithm, user direction, DS managing unit direction, controlunit direction, as a function of the data type, as a function of thedata segment 92 metadata, and/or any other factor to determine algorithmtype. The forward error correction algorithm may be Golay,Multidimensional parity, Reed-Solomon, Hamming, Bose Ray ChauduriHocquenghem (BCH), Cauchy-Reed-Solomon, or any other FEC encoder. Notethat the encoder 77 may use a different encoding algorithm for each datasegment 92, the same encoding algorithm for the data segments 92 of adata object, or a combination thereof.

The encoded data segment 94 is of greater size than the data segment 92by the overhead rate of the encoding algorithm by a factor of X/T, whereX is the width or number of slices, and T is the read threshold. In thisregard, the corresponding decoding process can accommodate at most X-Tmissing EC data slices and still recreate the data segment 92. Forexample, if X=16 and T=10, then the data segment 92 will be recoverableas long as 10 or more EC data slices per segment are not corrupted.

The slicer 79 transforms the encoded data segment 94 into EC data slicesin accordance with the slicing parameter from the vault for this userand/or data segment 92. For example, if the slicing parameter is X=16,then the slicer 79 slices each encoded data segment 94 into 16 encodedslices.

The post-slice manipulator 81 performs, if enabled, post-manipulation onthe encoded slices to produce the EC data slices. If enabled, thepost-slice manipulator 81 determines the type of post-manipulation,which may be based on a computing system-wide predetermination,parameters in the vault for this user, a table lookup, the useridentification, the type of data, security requirements, available DSNmemory, performance requirements, control unit directed, and/or othermetadata. Note that the type of post-slice manipulation may includeslice level compression, signatures, encryption, CRC, addressing,watermarking, tagging, adding metadata, and/or other manipulation toimprove the effectiveness of the computing system.

In an example of a read operation, the post-slice de-manipulator 89receives at least a read threshold number of EC data slices and performsthe inverse function of the post-slice manipulator 81 to produce aplurality of encoded slices. The de-slicer 87 de-slices the encodedslices to produce an encoded data segment 94. The decoder 85 performsthe inverse function of the encoder 77 to recapture the data segment90-92. The pre-slice de-manipulator 83 performs the inverse function ofthe pre-slice manipulator 75 to recapture the data segment 90-92.

FIG. 5 is a diagram of an example of slicing an encoded data segment 94by the slicer 79. In this example, the encoded data segment 94 includesthirty-two bits, but may include more or less bits. The slicer 79disperses the bits of the encoded data segment 94 across the EC dataslices in a pattern as shown. As such, each EC data slice does notinclude consecutive bits of the data segment 94 reducing the impact ofconsecutive bit failures on data recovery. For example, if EC data slice2 (which includes bits 1, 5, 9, 13, 17, 25, and 29) is unavailable(e.g., lost, inaccessible, or corrupted), the data segment can bereconstructed from the other EC data slices (e.g., 1, 3 and 4 for a readthreshold of 3 and a width of 4).

FIG. 6 is a flowchart that illustrates an example of storing of sliceswhere a DS processing module coordinates the determination of DS unitsto store slices to by way of a solicitation method described below. Themethod begins with step 96 where the DS processing module 34 obtainsdata for storage. For example, the DS processing module obtains the datafor storage based on receiving a data object to store (e.g., from a userdevice) 96. In another example, the DS processing module obtains thedata for storage based on retrieving data from a memory. Additionally,the DS processing module may receive a user ID, a data object name, andmetadata associated with the data object.

The method continues with step 98 where the DS processing moduledetermines metadata associated with the data. The metadata may includeone or more of but not limited to a hash of the data object, a priorityrequirement, a security requirement, a performance requirement, a sizeindicator, a data type indicator, a location requirement, and a user ID.The determination may be based on one or more of but not limited to themetadata, the user ID, the data object name, a data type indicator, thedata object, a calculated hash of the data object, a priority indicator,a security indicator, a performance requirement, a command, a user vaultlookup, geographic location of the user device, a location requirement,and a predetermination.

The method continues with step 100 where the DS processing moduledetermines target DS units. The determination may be based on one ormore of but not limited to the metadata, a DS unit list, geographiclocations of DS units, geographic location of the user device, acommand, a predetermination, a DSN memory status indicator, a DS unitsolicitation response history indicator, and a DSN memory performanceindicator. For example, the DS processing module selects a plurality ofDS units to send a solicitation broadcast message. As another example,the DS processing module interprets the metadata and determines the DSunits based on the metadata. As yet another example, DS processingmodule may select target DS units that are estimated to at least meetthe requirements indicated by the metadata and may meet otherrequirements imposed by a command or a predetermination. For instance,the DS processing module may target DS units with estimated sufficientmemory, that have not been solicited yet for this sequence, and that arewithin a five-mile radius of geographic proximity to the user device toprovide enhanced performance.

The method continues with step 102 where the DS processing moduledetermines and sends a solicitation message to solicit DS units to storeencoded data slices of the data. The DS processing module generates thesolicitation message to include one or more of but not limited to asolicitation request, the metadata, and storage requirements. The DSprocessing module sends the solicitation message to the target DS unitsby way of one or more of a broadcast message (e.g., all DS units), aunicast message (e.g., one DS unit at a time), and/or a multicastmessage (e.g., to a subset of DS units organized into a subset)transmission.

The method continues with step 104 where the DS processing moduledetermines whether favorable responses have been received from a set ofDS units. The DS processing module receives a solicitation response fromone or more DS units where the solicitation response includes afavorable or unfavorable indicator. The response may also include a DSunit capability indicator (e.g., how much memory is available, aperformance indicator, etc). A favorable indicator indicates that the DSunit is willing to store slices and an unfavorable indicator indicatesthat the DS unit is not willing to store slices. In another embodiment,the DS unit may only send a solicitation response that includes thefavorable indicator (e.g., it does not send a response with theunfavorable indicator). For example, the favorable responses may includeat least one of first storage requirements that substantially matchesrequirements of the soliciting. In other words, the DS unit can meet thestorage requirements. As another example, the favorable responses mayinclude second storage requirements that encompass the requirements ofthe soliciting. In other words, the DS unit can provide a capabilitythat is similar to storage requirements which may suffice. For instance,the favorable response may include a security storage requirement thatmay indicate that 128 bit encryption can be provided when a securitystorage requirement of the solicitation indicated that 256 bitencryption is required. In this example, the DS processing module maydetermine that 128 bit encryption encompasses the security requirementeven though it is not a direct match. The method of the DS unitdetermination of the solicitation response is discussed in greaterdetail with reference to FIG. 7.

The method continues with step 106 where the DS processing moduledetermines if sufficient favorable responses have been received based ona comparison of the storage requirements of the solicitation with theresponses. Note that the DS processing module may be executing asequence to store one slice, a batch of data segment slices for thepillar, more than one batch of data segment slices for one or morepillars, up to all slices for each data segment of the data object. Inother words, the DS processing module is looking for a sufficient numberDS units that will meet the sequence needs and meet the functional andperformance requirements based on the metadata.

The method branches to step 108 when the DS processing module determinesthat favorable responses have not been received so far. The methodbranches to step 110 when the DS processing module determines thatfavorable responses have been received. At step 108, the DS processingmodule determines if a timeout has occurred when the DS processingmodule determines that sufficient favorable responses have not beenreceived so far. The timeout time period may start when the DSprocessing module sent the solicitation message. The method branchesback to step 104 when the DS processing module determines that thetimeout has not occurred. The method branches back to step 100 when theDS processing module determines that the timeout has occurred. Note thatthe DS processing may try other DS units that were not sent thesolicitation message. Further note that the method may continue in thisloop for several iterations and in another embodiment, the DS processingmay retry DS units that have already been sent the solicitation message(e.g., the DS unit status may have changed).

At step 110, the DS processing module determines error coding dispersalstorage function parameters (e.g., operational parameters) based on oneor more of but not limited to interpreting the metadata, the favorableresponses, the number of favorably responding DS units, the DS unitcapability indicator, a command, a predetermination, and a user vaultlookup. The error coding dispersal storage function parameters includesat least one of a segmenting protocol, a pre-slice data manipulationfunction, a forward error correction, encoding function, a slicingpillar width, a post-slice data manipulation function, a writethreshold, and a read threshold. For example, the DS processing moduleinterprets the metadata and establishes a slicing pillar width inaccordance with the metadata. In an instance, the DS processing moduleinterprets the metadata to determine a reliability requirement andchooses the slicing pillar width to be 16 such that the pillar widthmeets the reliability requirement and when the number of favorableresponses from the DS units is equal to or greater than 16. In anotherexample, the DS processing module adjusts the error coding dispersalstorage function and/or the error coding dispersal storage functionparameters when the number of the favorable responses is less than theslicing pillar width. In an instance, the DS processing module maychoose a write threshold to be 15 when the slicing pillar width is 16but there were only 15 DS units returning favorable responses.

In another example, the DS processing module chooses the pillar width nto be less than the number of favorably responding DS units and muchlarger than the read threshold. In another example, the DS processingmay choose multiple DS unit storage sets comprising the favorablyresponding DS units such that the slices of different data segments maybe sent to different DS unit storage sets. The DS processing module mayinclude the storage set choices in the operational parameters.

In the continuation of step 110, DS processing module saves the errorcoding dispersal storage function parameters in the user vault and/oranother memory. The DS processing module may or may not save the DS unitchoices. The DS processing module may save the DS unit choices in a uservault, a virtual DSN address (e.g., slice name) to physical locationtable, and/or another memory. In one embodiment, the DS processingperforms subsequent slice retrievals through another solicitation methodwhen the DS processing does not save the DS unit choices. In anotherembodiment, the DS processing performs subsequent slice retrievals bylooking up in memory where the slices are stored when the DS processingsaves the DS unit choices. The retrieval method is discussed in greaterdetail with reference to FIGS. 8-9.

The method continues at step 112 where the DS processing module encodesthe data to produce encoded data slices in accordance with the favorableresponses and the error coding dispersal storage function utilizing theerror coding dispersal storage function parameters. The DS processingmodule sends the encoded data slices to the DS unit with a store commandfor subsequent storage in the DS units. Note that the DS processingmodule may send one slice, all the slices batched for a pillar of a datasegment, all the slices of a data segment, or all the slices of all thedata segments of the data object. The method may branch back to step 100where the DS processing determines target DS units when the DSprocessing is not finished creating and sending slices for the dataobject. For example, the loop described above may repeat for the nextdata segment.

FIG. 7 is a flowchart illustrating the response to a solicitation tostore slices where a DS unit determines how to respond to receiving asolicitation message from a DS processing module. The method may beimplemented in any one of a user device, a DS processing unit, a DSmanaging unit, a storage integrity processing unit, and a DS unit. Forexample, the method is implemented in the DS unit.

The method begins at step 114 where the DS unit receives thesolicitation message regarding dispersed storage of data from the DSprocessing 114. The solicitation message may include metadata and one ormore storage requirements regarding storage of encoded data slices ofthe data.

The method continues at step 116 where the DS unit determines itsavailability based on one or more of the metadata, DS unit status, DSunit memory availability, a command, a predetermination, historic DSunit performance, and DS unit loading. The DS unit compares the one ormore storage requirements with storage capabilities of the DS unit todetermine availability. For example, the DS unit compares the memoryrequirements from the solicitation message to the memory availabilityand determines that the DS unit is available for this solicitation whenthe amount of available memory is greater than the memory requirements.The method branches back to step 114 when the DS unit determines thatthe DS unit is not available. Alternatively, the DS unit sends asolicitation response message to the DS processing module that includesan unfavorable indicator.

The method continues at step 120 where the DS unit determines thesolicitation response message when the storage capabilities comparefavorably to the one or more storage requirements. The favorableresponse message may include the storage capabilities substantiallymatches the one or more storage requirements or the storage capabilitiessubstantially encompasses the one or more storage requirements. In anexample of a response that indicates the capabilities substantiallyencompasses the one or more storage requirements, the DS unit may offerto store a portion of the amount requested in the solicitation. Forinstance, the DS unit may indicate in response that it can store 500megabytes in the DS unit when the solicitation request metadataindicated that 1 gigabyte was requested. Note that the DS processingmodule adjusts the error coding dispersal storage function to reconcileany differences between the requirements and the responses by ensuringthat a sufficient number of DS units are available to meet the totalrequirements.

Next, at step 122, the DS unit sends a favorable response message to theDS processing module that sent the solicitation. The DS unit maysubsequently receive a store command, metadata, the object name, slicenames, and at least one of the encoded data slices of the data to storefrom the DS processing module. The DS unit stores the at least one ofthe encoded data slices in accordance with the one or more storagerequirements. In addition, the DS unit maintains a storage record of theat least one of the encoded data slices, wherein the record includes atleast one of: the one or more storage requirements, the storagecapabilities, a storage agreement, a slice name, a source name, a dataobject name, an integrity check value, and a storage location. Note thatthe storage agreement may include the capabilities provided to meet therequirements requested.

FIG. 8 is a flowchart illustrating the retrieving of slices where a DSprocessing module coordinates the determination of DS units to try toretrieve slices by way of a retrieval solicitation method describedbelow. The method begins at step 124 where the DS processing modulereceives a request to retrieve a data object (e.g., from a user device).The DS processing module may receive the user ID, the data object name,and metadata associated with the data object.

The method continues at step 126 where the DS processing moduledetermines metadata such that the metadata may include one or more ofbut not limited to a hash of the data object, a priority requirement, asecurity requirement, a performance requirement, a size indicator, adata type indicator, a location requirement, and a user ID. Thedetermination may be based on one or more of the received metadata, theuser ID, the data object name, a data type indicator, a previouslycalculated hash of the data object, a priority indicator, a securityindicator, a performance requirement, a command, a user vault lookup,geographic location of the user device, a location requirement, and apredetermination.

The method continues at step 128 where the DS processing moduledetermines target DS units where the target DS units represent DS unitsthat the DS processing will subsequently solicit to retrieve slices. Inother words, these are the DS units where the slices are most likelystored. The determination may be based on one or more of but not limitedto the metadata, a DS unit list, geographic locations of DS units,geographic location of the user device, a command, a predetermination, aDSN memory status indicator, a DS unit solicitation response historyindicator, and/or a DSN memory performance indicator. The DS processingmodule may select target DS units that are estimated to at least meetthe requirements indicated by the metadata and may meet otherrequirements imposed by a command or a predetermination. For example,the DS processing may target DS units with estimated sufficient memory,that have not been solicited yet for this sequence, and that are withina five-mile radius of geographic proximity to the user device to provideenhanced performance.

The method continues at step 130 where the DS processing moduledetermines a retrieval message for the target DS units that includes aretrieval request, the metadata, slice names (e.g., based on the dataobject name and determined as described in FIG. 3) and may includestorage requirements. At step 130, the DS processing module sends theretrieval message to the target DS units. Note that the DS processingmodule may send the retrieval message to the target DS units by way ofone or more of a broadcast message (e.g., all DS units), a unicastmessage (e.g., one DS unit at a time), and/or a multicast message (e.g.,to a subset of DS units organized into a subset) transmission.

The DS processing module receives a retrieval response from one or moreDS units where the retrieval response includes slices. The method of theDS unit determination of the retrieval response is discussed in greaterdetail with reference to FIG. 9.

The method continues at step 132 where the DS processing moduledetermines if sufficient responses have been received that in totalityinclude enough slices to create a data segment or a series of datasegments to create the data object. Note that the DS processing modulemay be in a sequence to retrieve one slice, a batch of data segmentslices for the same pillar, more than one batch of data segment slicesfor one or more pillars, up to all slices for each data segment of thedata object. In other words, the DS processing module is looking for asufficient number of slices to create the slice, data segment, and/ordata object. For example, the DS processing module may be looking for aread threshold k number of slices to recreate a data segment. Note thatthe DS processing module may determine the read threshold by a lookup inthe user vault for this user ID.

The method branches to step 134 where the DS processing moduledetermines whether a timeout has occurred when the DS processing moduledetermines that sufficient favorable responses has not been received sofar. The timeout time period may start when the DS processing sent theretrieval message. The method branches back to step 132 when the DSprocessing module determines that the timeout has not occurred. Themethod branches back to step 128 when the DS processing moduledetermines that the timeout has occurred. Note that the DS processingmodule may try other DS units that were not sent the retrievalsolicitation so far. Further note that the method may continue in thisloop for several iterations and in another embodiment, the DS processingmay retry DS units that have been sent the retrieval solicitationmessage (e.g., the DS unit status may have changed).

The method continues at step 136 where the DS processing moduledetermines error coding dispersal storage function parameters based onone or more of but not limited to the metadata, the number of favorablyresponding DS units, the DS unit capability indicator, a command, apredetermination, and a user vault lookup. For example, the DSprocessing module may retrieve the storage set information from the uservault. In another example, the DS processing may retrieve multiple DSunit storage sets from the user vault when the encoded data slices ofdifferent data segments were sent to different storage sets. In anotherembodiment, the DS processing module performs slice retrievals bylooking up in memory where the slices are stored when the DS processingmodule previously saved the DS unit choices.

The method continues with step 138 where the DS processing modulede-slices and decodes the retrieved slices of the data object torecreate the data segment(s) in accordance with error coding dispersalstorage function and the favorable responses. The DS processing modulerecreates the data object by recreating the data segments. Note that themethod described above may loop until all of the data segments areavailable to form the data object. The DS processing module sends thedata object to the requester.

FIG. 9 is a flowchart illustrating the response to a solicitation toretrieve slices where the DS unit determines how to respond to receivinga retrieval message from a DS processing module. The method may beimplemented in any one of a user device, a DS processing unit, a DSmanaging unit, a storage integrity processing unit, and a DS unit. Forexample, the method is implemented in the DS unit.

The method begins at step 140 where the DS unit receives a retrievalmessage that includes identities of a set of encoded data slices. Theretrieval message may include a retrieval command, metadata, the slicenames (e.g., identities), and/or the data object name.

The method continues at step 142 where the DS unit determines whether anencoded data slice of the set of encoded data slices is identified in astorage record based on one or more of a lookup in a local virtual DSNaddress to physical location table, a storage table lookup, themetadata, DS unit status, DS unit memory availability, a command, apredetermination, historic DS unit performance, and DS unit loading. Forexample, the DS unit compares the slice names from the retrieval messageto the slice names in the local virtual DSN address to physical locationtable to look for a match (e.g., present). The method branches back tostep 140 when the DS unit determines that the encoded data slice of theset of encoded data slices is not identified in the storage record. Inaddition, the DS unit may send a retrieval response message to the DSprocessing that indicates that the slice is not present. The methodcontinues to step 144 when the DS unit determines that the encoded dataslice of the set of encoded data slices is identified in this storagerecord.

The method continues with step 144 where the DS unit retrieves theencoded data slice(s) when the encoded data slice is identified in therecord. The DS unit may determine where to retrieve the slice(s) from bylooking up the location in the local virtual DSN address to physicallocation table. In an example, the encoded data slices are stored in thepresent DS unit. In another example, the slices are stored in at leastone other DS unit. The method continues with step 146 where the DS unitsends a message that includes the encoded data slice as a retrievalresponse to the DS processing module that sent the solicitation for theencoded data slice(s).

FIG. 10 is another flowchart illustrating the storing of slices where aDS processing module initiates the storing of slices to a plurality ofDS units in a serial fashion as described in the method below. Themethod begins with step 148 where the DS processing module obtains datafor storage. For example, the DS processing module receives a dataobject to store (e.g., from a user device). The DS processing module mayreceive a user ID, a data object name, and metadata associated with thedata object. In another example, the DS processing module retrieves datafrom a local memory to obtain the data for storage.

The method continues with step 150 where the DS processing moduledetermines a proxy unit (e.g., a seed DS unit) where the DS processingmodule sends an initial batch of encoded data slices. In an example, theDS processing module selects one of the plurality of DS units as theproxy unit. The determination may be based on one or more of but notlimited to a random choice, the metadata, a DS unit list, geographiclocations of DS units, geographic location of the user device, acommand, a predetermination, a DSN memory status indicator, a DS unithistory indicator, and a DSN memory performance indicator. For instance,the DS processing module may select the proxy unit that isgeographically close to the user device and has a history of sufficientreliability and performance.

The method continues at step 152 where the DS processing moduledetermines metadata where the metadata may include one or more of butnot limited to a hash of the data object, a priority requirement, asecurity requirement, a performance requirement, a size indicator, adata type indicator, a location requirement, and a user ID. Thedetermination may be based on one or more of received metadata, the userID, the data object name, a data type indicator, the data object, acalculated hash of the data object, a priority indicator, a securityindicator, a performance requirement, a command, a user vault lookup,geographic location of the user device, a location requirement, and apredetermination.

The DS processing module determines error coding dispersal storagefunction parameters (e.g., operational parameters) based on one or moreof but not limited to the metadata, a capability indicator of the seedDS unit, a command, a predetermination, and a user vault lookup. Forexample, the DS processing module may choose the pillar width n to bemuch larger than the read threshold k for storing a data segment in astorage set when utilizing this method. In another example, the DSprocessing module may choose multiple storage sets comprising one ormore seed DS units such that the slices of different data segments maybe sent to different storage sets (e.g., resulting in different trails).The DS processing module may include the storage set choices (e.g.,pillar width n and the seed DS unit ID) in the error coding dispersalstorage function parameters.

The DS processing module may save the error coding dispersal storagefunction parameters in the user vault, in the metadata, and/or anothermemory. The DS processing module may or may not save the proxy unitchoices (e.g., per slice name and/or data segment ID) in the user vault,a virtual DSN address (e.g., slice name) to physical location table,and/or another memory. For example, the DS processing module performssubsequent slice retrievals through another method when the DSprocessing does not save the seed DS unit choices. As another example,the DS processing module performs subsequent slice retrievals by lookingup in memory where the slices are stored when the DS processing savesthe seed DS unit choices. The retrieval method is discussed in greaterdetail with reference to FIGS. 12-13.

The method continues at step 154 where the DS processing module encodesthe data in accordance with an error coding dispersal storage functionto produce a plurality of sets of encoded data slices. In step 156, DSprocessing module appends the metadata to the slices. In step 156, theprocessing module transmits the metadata to the proxy unit, wherein themetadata includes a dispersal approach regarding how the proxy unit isto disperse the plurality of sets of encoded data slices. The dispersalapproach may include at least one of: disperse in a sequential fashion,disperse in a daisy chain fashion, disperse in a one-to-many fashion,and forward to a second proxy unit, wherein the second proxy unitdisperses the plurality of sets of encoded data slices to the pluralityof dispersed storage units. In step 156, a processing module transmitsthe plurality of sets of encoded data slices to the proxy unit, whereinthe proxy unit disperses the plurality of sets of encoded data slices toa plurality of dispersed storage (DS) units in accordance with thedispersal approach. Note that the DS processing may send one slice, allthe slices batched for a pillar of a data segment, all the slices of adata segment, all the slices of all the data segments of the dataobject. The method may branch back to step 150 when the DS processingmodule is not finished creating and sending slices for the data object.For example, the steps described above may repeat for the next datasegment.

The method continues at step 158 where the DS processing module receivesdispersed storage information (e.g., updated metadata) regardingdispersed storage of the plurality of sets of encoded data slices. TheDS processing module may receive may receive the dispersed storageinformation from at least one DS unit along the storage trail. Thedispersed storage information includes one or more of: an encoded dataslice storage confirmation identifier, a DS unit identifier and at leastone associated slice name, a seed DS unit identifier, an end DS unitidentifier, and storage path information. Note that the DS unitidentifier pertains to a DS unit along the storage trail. In otherwords, the trail may indicate which DS units stored which portions(e.g., slice names) of the slices.

In step 160, the DS processing module saves the updated dispersedstorage information in one or more of the user vault, a virtual DSNaddress (e.g., slice name) to physical location table, and anothermemory. Note that the DS processing module may retrieve the encoded dataslices in a serial fashion starting with slices stored at the proxyunit. Further note that the error coding dispersal storage functionparameters may be optimized to facilitate faster data segment decodingby including data bits of the data object in a first grouping of theslices and including parity/error correction bits in a second groupingof the slices. In this fashion the first encoded data slices retrievedmay contain everything to decode the data segment (e.g., when there areno errors) without retrieving further slices.

FIG. 11 is another flowchart illustrating the response to a solicitationto store slices where a DS unit determines how to respond to receivingslices to store from a DS processing module. The method may beimplemented in any one of a user device, a DS processing unit, a DSmanaging unit, a storage integrity processing unit, and a DS unit. Forexample, the method is implemented in the DS unit.

The method begins at step 162 where the DS unit receives a plurality ofsets of encoded data slices (e.g., a pillar of slices for two or moredata segments) and metadata associated with the plurality of sets ofencoded data slices. In addition, the DS unit may receive a storecommand and slice names from the DS processing module or from another DSunit when the present DS unit is not a proxy unit in a storage trail.Note that the slices may include slices of one or more data segments andone or more pillars.

The method continues at step 164 where the DS unit determines itsavailability based on one or more of the metadata, DS unit status, DSunit memory availability, a command, a predetermination, historic DSunit performance, and DS unit loading. For example, the DS unit comparesthe memory requirements from the metadata to the memory availability anddetermines that the DS unit is available for this solicitation when theamount of available memory is greater than the memory requirements(e.g., to store at least a portion of the slices). The method branchesto step 170 when the DS unit determines that it is available. The methodcontinues to step 166 when the DS unit determines that it is notavailable.

In step 166, the DS unit determines a next DS unit. Alternatively or inaddition to, the DS unit sends a storage response message to the DSprocessing module that includes a not available indicator (e.g., so theprocess may avoid this DS unit at least for a time period). The DS unitdetermines the next DS unit based on one or more of but not limited tothe trail in the metadata, a routing table entry in a router connectingDS unit functions, a random choice, the metadata, a DS unit list,geographic locations of DS units, geographic location of the userdevice, a command, a predetermination, a DSN memory status indicator, aDS unit history indicator, and a DSN memory performance indicator. Forexample, the DS unit may select the next DS unit that is geographicallyclose to the current DS unit (e.g., as indicated by the routing table),has a history of sufficient reliability and performance, and is not inthe trail yet.

Next, at step 168, the DS unit sends the store command, encoded dataslices, slice names, and metadata to the next DS unit. The DS unitinterprets the metadata to determine storage instructions regarding theplurality of encoded data slices. For example, the DS unit may interpretthe metadata to determine the storage instructions indicate daisy chainstorage or one-to-many storage. In an example of a daisy chain storage,at step 170, the DS unit locally stores first encoded data slices ofeach set of encoded data slices and may update the local virtual DSNmemory to physical location table. Note that the DS unit may only storeas much as it determines it can store (e.g., based on available memoryand the amount requested). Further note that the DS unit may only storeslices of the same pillar number to improve system reliability.

The method continues at step 172 where the DS unit updates the metadatato produce updated metadata and locally stores the updated metadata. Forexample, the DS unit updates the metadata by adding the DS unit ID toproduce the updated metadata (e.g., updated trail).

The method continues at step 174 where the DS unit determines if the DSunit is an end DS unit (e.g., the last slice has been stored) byinspecting the slice batch and what was stored locally. The methodbranches to step 180 when the DS unit determines that the last encodeddata slice was stored locally. The method continues to step 176 when theDS unit determines that the last encoded data slice was not storedlocally. At step 176 and the DS unit determines a next DS unit. The DSunit determines the next DS unit based on one or more of but not limitedto the trail in the metadata, a routing table entry in a routerconnecting DS unit functions, a random choice, the metadata, a DS unitlist, geographic locations of DS units, geographic location of the userdevice, a command, a predetermination, a DSN memory status indicator, aDS unit history indicator, and a DSN memory performance indicator. Forexample, the DS unit may select the next DS unit that is geographicallyclose to the current DS unit (e.g., as indicated by the routing table),has a history of sufficient reliability and performance, and is not inthe trail yet. At step 178, the DS unit forwards other encoded dataslices of the sets of encoded data slices to at least one other DS unit(e.g., the next DS unit). Additionally, the DS unit may send the storecommand, slice names, and the updated metadata to the at least one otherDS unit (e.g., the next DS unit).

The method continues at step 180 where the DS unit forwards the updatedmetadata to the DS processing module when the DS unit is the end DSunit. Alternatively, the DS unit may forward the updated metadata to theDS processing module when the DS unit is not the end unit. In addition,the DS unit may temporarily cache one up to all of the received slicesand receive a confirmation from the DS processing unit or another DSunit that all of the slices have been stored before deleting the cachedslices.

In an example of operation when the storage instructions indicateone-to-many storage, the DS unit transmits pillar numbered encoded dataslices of the plurality of sets of encoded data slices to correspondingones of a plurality of DS units, wherein the plurality of DS unitsincludes the at least one other DS unit. For example, the DS unittransmits the slices for pillar 1 for each segment to DS unit one inparallel with transmitting the slices of pillar 2 for each segment to DSunit 2 in parallel with transmitting the slices of pillar three for eachdata segment to DS unit 3, etc. until the slices of all n (e.g., slicingpillar width) pillars for all segments are transmitted to DS units.

FIG. 12 is another flowchart illustrating the retrieving of slices wherea DS processing module determines a first target DS unit to start toserially retrieve encoded data slices DS unit by DS unit via a retrievalmethod described below. The DS processing module may be implemented inany one of a user device, a DS processing unit, a DS managing unit, astorage integrity processing unit, and a DS unit. For example, the DSprocessing module is implemented in the DS processing unit.

The method begins at step 182 where the DS processing module receives arequest to retrieve a data object (e.g., from a user device). The DSprocessing module may receive the user ID, the data object name, andmetadata associated with the data object.

The method continues at step 184 where the DS processing moduledetermines metadata. The metadata may include one or more of but notlimited to a hash of the data object, a priority requirement, a securityrequirement, a performance requirement, a size indicator, a data typeindicator, a location requirement, and a user ID. The determination maybe based on one or more of the received metadata, a user ID, the dataobject name, a data type indicator, a previously calculated hash of thedata object, a priority indicator, a security indicator, a performancerequirement, a command, a user vault lookup, geographic location of theuser device, a location requirement, and a predetermination.

In step 184, the DS processing module determines the error codingdispersal storage function parameters (e.g., operational parameters)based on one or more of but not limited to the metadata, a DS unitcapability indicator, a command, a predetermination, and a user vault.For example, the DS processing module retrieves the error codingdispersal storage function parameters including a DS unit storage setinformation from the user vault. In another example, the DS processingmodule retrieves multiple DS unit storage sets from the user vault whenthe slices of different data segments were sent to different DS unitstorage sets.

The method continues at step 186 where the DS processing moduledetermines a first target DS unit (e.g., proxy unit) where the target DSunit represents the seed DS unit that the DS processing modulepreviously utilized to start the storage of slices. In other words, thisis the DS unit where the slices were most likely first stored. Thedetermination may be based on one or more of but not limited to themetadata, a lookup in the user vault, a DS unit list, geographiclocations of DS units, geographic location of the user device, acommand, a predetermination, a DSN memory status indicator, a DS unitresponse history indicator, and a DSN memory performance indicator. TheDS processing module may select the first target DS unit that isestimated to at least meet the requirements indicated by the metadataand may meet other requirements imposed by a command or apredetermination. For example, the DS processing module chooses thefirst target DS unit with estimated sufficient memory, that has not beenchosen yet for this sequence, and that is within a five-mile radius ofgeographic proximity to the user device to provide enhanced performance.

The method continues at step 188 where the DS processing moduledetermines a retrieval message for the first target DS unit thatincludes a retrieval request, the metadata, the slice names (e.g., basedon the data object name and determined as described in FIG. 3). In step188, the DS processing module sends the retrieval message to the firsttarget DS unit. Note that the DS processing module may determine morethan one first target when more than one DS unit storage set isutilized. Further note that the DS processing module may send theretrieval message to the first target DS unit(s) by way of one or moreof a broadcast message (e.g., all DS units), a unicast message (e.g.,one DS unit at a time), and a multicast message (e.g., to a subset of DSunits organized into a subset) transmission.

The method continues at step 190 where the DS processing module receivesa retrieval response from one or more DS units where the retrievalresponse includes encoded data slices. The method of the DS unitdetermination of the retrieval response is discussed in greater detailwith reference to FIG. 13.

The method continues at step 192 where the DS processing moduledetermines if enough slices have been received from the retrievalresponses to create a data segment or a series of data segments tore-create the data object. Note that the DS processing module may be ina sequence to retrieve one slice, a batch of data segment slices for thesame pillar, more than one batch of data segment slices for one or morepillars, up to all slices for each data segment of the data object. Inother words, the DS processing module is looking for a sufficient numberof slices to create the slice, data segment, and/or data object. Forexample, the DS processing module may be looking for a read threshold knumber of slices to re-create a data segment. Note that the DSprocessing module may determine the read threshold from the error codingdispersal storage function parameters (e.g., by a lookup in the uservault for this user ID).

The method branches to step 196 when the DS processing module determinesthat enough coded data slices have been received. The method continuesto step 194 when the DS processing module determines that enough codeddata slices have not been received. In step 194, the DS processingdetermines the next DS unit. The determination may be based on the DSunit trail in the metadata (e.g., a linked list of one DS unit to thenext where the slices were previously stored). The method branches backto step 188 sends a retrieval message to the next DS unit. Note that themethod may continue in this loop for several iterations. Additionally,the DS processing module may retry at least one DS unit that waspreviously tried (e.g., the DS unit may have been off line).Alternatively, the DS processing module performs encoded data sliceretrievals by looking up in memory where the slices are stored when theDS processing module previously saved the DS unit choices.

The method continues at step 196 where the DS processing modulede-slices and decodes the retrieved slices of the data object torecreate the data segment(s) in accordance with the error codingdispersal storage function parameters when the DS processing determinesthat enough encoded data slices have been received. The DS processingmodule re-creates the data object by recreating the data segments. Notethat the method described above may loop until all of the data segmentsare available to aggregate into the data object. The DS processingmodule sends the data object to the requester.

FIG. 13 is another flowchart illustrating the retrieving of slices wherethe DS unit determines how to respond to receiving a retrieval messagefrom the DS processing or another DS unit when the slices may be storedserially at different DS units. The method may be implemented in any oneof a user device, a DS processing unit, a DS managing unit, a storageintegrity processing unit, and a DS unit. For example, the method isimplemented in the DS unit.

The method begins at step 198 where the DS unit receives the retrievalmessage from an initiator (e.g., the DS processing module). Theretrieval message may include a retrieval command, metadata, a pool ofslices retrieved so far (e.g., from other DS units on the same trail),slice names, and a data object name.

The DS unit determines whether the slices are locally stored based onone or more of a lookup in a local virtual DSN address to physicallocation table, the metadata, DS unit status, DS unit memoryavailability, a command, a predetermination, historic DS unitperformance, and DS unit loading. For example, the DS unit compares theslice names from the retrieval message to the slice names in the localvirtual DSN address to physical location table to look for a match(e.g., present). The method branches back to step 198 when the DS unitdetermines that the slice(s) are not present. Alternatively, the DS unitsends a retrieval response message to the initiator (e.g., the DSprocessing module) that indicates that the encoded data slice is notpresent.

The DS unit retrieves locally stored metadata in response to theretrieval message. In step 200, the DS unit retrieves locally storedencoded data slices in accordance with the locally stored metadata. TheDS unit may determine where to retrieve the slice(s) from by looking upthe location in the local virtual DSN address to physical locationtable. In an example, the encoded data slices are stored in the presentDS unit. In another example, the encoded data slices are stored in atleast one other DS unit.

The method continues at step 202 where the DS unit updates the metadatawith the DS unit ID to produce updated metadata and updates theretrieved encoded data slices pool (e.g., the aggregation of all theslices retrieved so far along the DS unit storage trail). Note that themetadata now indicates that the slice pool includes slices retrievedfrom the present DS unit. The DS unit may send the stored encoded dataslices to the initiator and/or forward the retrieval message and encodeddata slices to the at least one other DS unit in accordance with thelocally stored metadata.

The method continues at step 204 where the DS unit determines whetherenough encoded data slices have been retrieved when either the DS unitdetermines that all of the possible slices have been retrieved from theDS unit storage trail or when the DS unit determines that the slice poolnow contains at least a read threshold number of slices (e.g., the readthreshold from the metadata). The method continues to step 206 when theDS unit determines that there are not enough encoded data slices. Atstep 206, the DS unit determines the next DS unit based on the DS unitstorage trail in the metadata. The method continues at step 208 wherethe DS unit sends the retrieval message to the next DS unit where theretrieval message includes the retrieval command, the updated metadata,the pool of retrieved slices so far (e.g., from other DS units on thesame trail), the slice names, and/or the data object name. The next DSunit may append more slices to the slice pool until either all theslices have been retrieved or a read threshold number of slices has beenretrieved as previously described.

The method branches to step 210 when the DS unit determines that thereare enough encoded data slices. At step 210, the DS unit sends theretrieval message (e.g., including the retrieved slice pool and updatedmetadata) to the initiator (e.g., the DS processing that sent theretrieval request) such that the initiator can decode the encoded dataslices as previously discussed.

FIG. 14 is another flowchart illustrating the storing of slices wherethe DS unit 36 coordinates the determination of other DS units to storeslices to by way of a solicitation method described below. The methodbegins at step 212 where the DS unit receives one or more encoded dataslices to store (e.g., from the DS processing 34).

The method continues at step 214 where the DS unit determines metadataassociated with the one or more encoded data slices. The metadataincludes one or more of, but is not limited to a hash of the dataobject, a hash of the slices, a priority requirement, a securityrequirement, a performance requirement, a data object size indicator, adata segment size indicator, a slice size indicator, a data typeindicator, a location requirement, and/or a user ID. The determinationmay be based on one or more of the metadata, a user ID, a data objectname, the slice names, the slices, a data type indicator, the dataobject, a calculated hash of the data object, a calculated hash of thedata segment, a calculated hash of the slice, a priority indicator, asecurity indicator, a performance requirement, a command, a user vaultlookup, geographic location of the user device, a location requirement,and/or a predetermination.

The method continues at step 216 where the DS unit determines whether tostore at least a portion of the slices locally based on one or more ofthe metadata, DS unit status, DS unit memory availability, a command, apredetermination, historic DS unit performance, and/or DS unit loading216. For example, the DS unit compares the memory requirements from themetadata to the memory availability and, when the comparison isfavorable, indicates that it can store at least some of the sliceslocally and stores the slices locally at step 218.

When the DS unit cannot store all of the encoded data slices locally,the method continues at step 220 where the DS unit determines one ormore target DS units that may be able to store at least one of theslices. Such a determination may be based on one or more of themetadata, a DS unit list, geographic locations of DS units, geographiclocation of the user device and/or DS processing unit, a command, apredetermination, a DSN memory status indicator, a DS unit solicitationresponse history indicator, and/or a DSN memory performance indicator.For example, the DS unit may select target DS units that are estimatedto at least meet the requirements indicated by the metadata and may meetother requirements imposed by a command or a predetermination.

The message continues at step 222 where the DS unit generates asolicitation message and sends it to the target DS units. Note that theDS unit may send the solicitation message to the target DS units by wayof one or more of a broadcast (e.g., all DS units), a unicast (e.g., oneDS unit at a time), and/or a multicast (e.g., to a subset of DS unitsorganized into a subset) transmission.

The method continues at step 224 where the DS unit determines whether ithas a received one or more favorable responses to its solicitationmessage. The response may include a DS unit capability indicator (e.g.,how much memory is available, a performance indicator, etc). When lessthan a sufficient amount of favorable responses have been received(i.e., for the slices that cannot be stored locally, one or more targetDS units with enough memory to store the slices have favorablyresponded), the method continues at step 226 where a time out mechanismis enabled. If the time out period has not expired, the method repeatsat step 224. If the timeout period has expired, the method repeats atstep 220.

When a sufficient amount of favorable responses have been received, themethod continues at step 228 where the DS unit determines operationalparameters (e.g., discussed with reference to FIG. 3) and stores them.Such a determination may be based on one or more of the metadata, thenumber of favorably responding DS units, the DS unit capabilityindicator, a command, a predetermination, and/or a user vault lookup.For example, the DS unit may choose the pillar width n to be less thanthe number of favorably responding DS units and much larger than theread threshold k for storing a data segment in a storage set whenutilizing the solicitation method. In another example, the DS unit maychoose multiple storage sets that include the favorably responding DSunits such that the slices of different data segments may be sent todifferent storage sets. The DS unit may include the storage set choicesin the operational parameters.

The method continues at step 230 where the DS unit encodes and slicesthe received slices to create further slices for distribution inaccordance with the operational parameters. For example, the DS unitpasses the received slices directly to the chosen solicited DS units.The DS unit sends the slices to the chosen solicited DS units with astore command for subsequent storage in the chosen solicited DS units inaccordance with the operational parameters 230. Note that the DS unitmay send one slice, all the slices batched for a pillar of a datasegment, all the slices of a data segment, or all the slices of all thedata segments of the data object.

FIG. 15 is another flowchart illustrating another example of retrievingof slices where the DS unit determines which other DS units to try toretrieve slices from by way of a retrieval solicitation method describedbelow. The method begins at step of the DS unit receiving a request toretrieve slices (e.g., from a DS processing) 232. Note that the requestmay be for one or more slices. Further note that the DS unit may receivethe slice names, the DS processing ID, the user ID, the data objectname, and metadata associated with the data object.

The method continues at step 234 where the DS unit determines metadatabased on one or more of the received metadata, the user ID, the DSprocessing ID, the data object name, a data type indicator, a previouslycalculated hash of the data object, a previously calculated hash of datasegments, a priority indicator, a security indicator, a performancerequirement, a command, a user vault lookup, geographic location of theuser device, a location requirement, and/or a predetermination. Themethod continues at step 236 where the DS unit determines whether theslices are stored locally based on one or more of a lookup in a localvirtual DSN address to physical location table, the metadata, DS unitstatus, DS unit memory availability, a command, a predetermination,historic DS unit performance, and/or DS unit loading 236. For example,the DS unit compares the slice names from the retrieval request to theslice names in the local virtual DSN address to physical location tableto look for a match (e.g., stored locally).

When at least some of the slices are stored locally, the methodcontinues at step 238 where the DS unit retrieves the locally storedslices. The method continues at step 240 where the DS unit sends theslices to a requesting device (e.g., the DS processing unit 34).

When at least some of the slices are not locally stored, the methodcontinues at step 242 where the DS unit determines target DS units,which store the other slices. Such a determination may be based on oneor more of the metadata, a DS unit list, geographic locations of DSunits, geographic location of the user device, a command, apredetermination, a DSN memory status indicator, a DS unit solicitationresponse history indicator, and/or a DSN memory performance indicator.The DS unit may select target DS units that are estimated to at leastmeet the requirements indicated by the metadata and may meet otherrequirements imposed by a command or a predetermination.

The method continues at step 244 where the DS unit generates a retrievalmessage (e.g., a retrieval request, the metadata, slice names, and/or arequirements summary) and sends it to the target DS units. Note that theDS unit may send the retrieval message to the target DS units by way ofone or more of a broadcast (e.g., all DS units), a unicast (e.g., one DSunit at a time), and/or a multicast (e.g., to a subset of DS unitsorganized into a subset) transmission.

The method continues at step 246 where the DS unit receives a retrievalresponse from one or more DS units. The retrieval response includes theslices, the identity of the target DS unit, and or other relevantinformation. If the DS unit has not received a favorable number ofslices (e.g. in combination with the locally stored slices, a readthreshold number), the method continues at step 248 where a timeoutmechanism is activated. If the timeout mechanism has not expired, themethod repeats at step 246. If, however, the timeout mechanism hasexpired, the method repeats at step 242.

When the DS unit has received a favorable number of slices, the methodcontinues at step 250 way or the DS unit determines operationalparameters (e.g., discussed with reference to FIG. 3) based on one ormore of the metadata, the number of favorably responding DS units, theDS unit capability indicator, a command, a predetermination, and/or auser vault lookup when the DS unit determines that sufficient favorableresponses have been received. The method continues at step 252 where arethe DS units de-slices and decodes the retrieved slices to recreate thedata segment(s) and/or slices in accordance with the operationalparameters. The DS processing then sends the reconstructed slices and/ordata segments to the requester.

FIG. 16 is a schematic block diagram of an embodiment of a socialtelevision media storage system. As illustrated, the system includes acable head end 256, a hybrid fiber coax (HFC) distribution 258, aplurality of viewers 1-V, a plurality of set top boxes 1-V (e.g.,computers, cable set top boxes, satellite receivers, home entertainmentsystems, and/or electronic devices with memory and a computing core),the network 24, and the DSN memory 22. Members of the social network mayinvoke recording of cable television content via their set top boxes,where media content is distributedly stored on other set top boxes ofother members of the social network and/or in the DSN memory 22.

The cable head end 256 may source broadcast, multicast, and/or unicastmedia content 260 via the HFC distribution 258 to the plurality of settop boxes 1-V. Alternatively, a satellite receiving system maysubstitute for the cable head end 256 and/or HFC 258. In anotheralternative, a content server (e.g., via the internet) and network 24connection may substitute for the cable head end 256 and/or HFC 258.

The set top box may include the computing core 26 of FIG. 2, a memory254, and the DS processing module 34. The DS processing module functionsto transform media content into encoded data slices for storage andsubsequent retrieval. The DS processing module 34 further functions toretrieve, de-slice, and decode encoded data slices to produce media datafor viewing. The DS processing 34 may utilize the memory 254 to storemedia content 260 including media content in the form of encoded dataslices. The set top box may select media content 260 from the cable headend 256 (e.g., broadcast/multicast or on-demand video over cable,satellite and/or the internet), stored media content 260 from the memory254, stored media content 260 in other set top boxes, and/or mediacontent 260 from the DSN memory 22. Note that the set top box mayfunction as a DS unit to store slices.

As illustrated, the viewer includes a flat panel television and/or othertype of display and speakers to reproduce the media. The viewerreproduces the media content (e.g., video, audio, pictures, web content)based on media content output from the set top box. The DS processingtransforms the media content into a format compatible with the viewer1-V. Alternatively, the functions of the set top box and the viewer areintegrated together. For example, the viewer may connect either directlyto other viewers and/or the DSN memory 22 to store and retrieve mediaslices.

In an example of operation, the DS processing module receives mediacontent from the cable head end 256 in response to a selection. The DSprocessing selects the media content based on one or more of but notlimited to selecting the media content from a media selection list,receiving a command from a media content source, and receiving a requestfrom another member of the local social network (e.g., another memberrequests storage on their behalf). The media content may include one ormore of but not limited to receiving the media content from a commercialmedia content provider, receiving the media content from a private mediacontent provider, and receiving the media content from a member of thelocal social network.

The DS processing module determines social media metadata regarding themedia content. The determination may be based on one or more of but notlimited to determining other members of the local social network,determining that the other members have not previously encoded andfacilitated storage of the media content, determining that at least oneof the other members has indicated a desire to encode and facilitatestorage of the media content, and receiving the social media metadatafrom a local social network manager.

The DS processing module determines if the social media metadataindicates that the media content is to be available for a local socialnetwork. For example, the DS processing module determines that the mediacontent is to be available for the local social network when the DSprocessing module determines that the social media metadata indicatesthat at least one of the other members has indicated a desire to encodeand facilitate storage of the media content.

The DS processing module encodes the media content to produce aplurality of sets of encoded data slices, identifies a plurality ofmemories, and sends the plurality of sets of encoded data slices to theplurality of memories to facilitate storage, as described in greaterdetail below, when the DS processing module determines that the socialmedia metadata indicates that the media content is to be available forthe local social network.

The DS processing module determines which portion of the media contentto store based on a selection. For example, the viewer and/or set topbox may indicate the selection to record or store in memory the 5:30 pmevening news on cable channel 188 on October 18 such that the viewer maysubsequently access the content.

The DS processing module determines which media content element (e.g. aportion of the media content such as a particular show or program)stored in the memory 254 to distributedly store. The determination maybe based on one or more of a command, a command from the cable head end256, a command from at least one other set top box, a memory utilizationindicator, and/or a predetermination. In another example, the DSprocessing module determines to distributedly store a movie when thememory utilization indicator is above a threshold (e.g., indicating thatthe memory 254 is almost full).

The DS processing module encodes the media content (e.g., media contentelement) in accordance with an error coding dispersal storage functionto produce a plurality of sets of encoded data slices (e.g., sets ofslices for each pillar of each data segment). The DS processing moduleidentifies a plurality of memories to store the plurality of sets ofencoded data slices. The plurality of memories includes one or more ofbut not limited to a memory associated with the distributed storageprocessing module of the current set top box, a memory within a memberof the local storage network, and a memory of a dispersed storagenetwork.

Alternatively, the DS processing module determines a method todistributedly store the media content element where the method mayinclude one or more of the methods discussed previously with referenceto FIGS. 6-15. The determination may be based on one or more of thesocial media metadata (e.g., availability of a group of set top boxeswho share content to store encoded data slices), a performancerequirement, a command, a command from the cable head end 256, a commandfrom at least one other social network number set top box, a memoryutilization indicator, and/or a predetermination. For example, the settop box may determine to utilize the solicitation method (e.g.,discussed with reference to FIG. 6) where the target memories maycomprise a plurality of set top boxes of the social network comprising asubset of the set top boxes 1-V. In other words, the DS processingmodule determines to distribute encoded data slices of the media contentelement to other set top boxes of the social network. In anotherexample, the plurality of target memories may include one or more layersof organization of set top boxes from the plurality of set top boxes1-V. Note that another layer may include one or more of a differentsocial network, a physical location (e.g., set top boxes in the samebuilding, set top boxes in the same neighborhood, set top boxes in thesame city, etc.). Further note that the DS processing module maydetermine to utilize one or more DS units 36 of the DSN memory 22.

The multiple set top boxes may determine to distributedly store the samecontent element. For example, the set top box determines whether atleast one other set top box in the social group of the set top box haspreviously distributedly stored the same content 260. The determinationmay be made based on one or more of a lookup in a table, querying atable in the other set top boxes of the same social group, querying atable in the user vault, querying a table in the DSN memory 22,searching the memory 254 in the other set top and/or boxes of the samesocial group.

The DS processing module sends the plurality of sets of encoded dataslices to the plurality of memories identified as described above. Inaddition, the DS processing module may update one or more tables (e.g.,and not re-store slices of the same content element) when the DSprocessing module determines that at least one other set top box in thesocial network of the set top box has distributedly stored the samemedia content. The DS processing module may update one or more tables,create EC data slices from the content element, and send the slices witha store command to the storage locations (e.g., determined by the methodto distributedly store the content element) when the set top boxdetermines that none of the other set top boxes in the social group ofthe set top box has distributedly stored the same content element. Inanother example, the DS processing module may update one or more tables,create EC data slices from the content element, and send the encodeddata slices with a store command to the storage locations to facilitatestorage (e.g., determined by the method to distributedly store thecontent element) when the set top box determines that at least one ofthe other set top boxes in the social network of the DS processingmodule has distributedly stored the same content element.

The DS processing module of the set top box retrieves encoded dataslices of the media content, recreates the media content from theencoded data slices, and presents the media content to the viewer asdescribed below. The set top box determines the method to distributedlyretrieve the content element where the method may include one or more ofthe methods discussed previously with reference to FIGS. 6-15. In aninstance, the determination may be made as previously discussed. Forexample, the set top box determines to utilize the solicitation method(e.g., discussed with reference to FIGS. 8-9) to retrieve slices wherethe target DS units 36 may be the social group comprising a subset ofthe set top boxes 1-V.

In an example of retrieval, the set top box retrieves content elementsthat the set top box previously stored distributedly (e.g., or any ofthe set top boxes invoked storing the content element) based ontranslating a media content ID (or accessing a DSN directory) into avirtual DSN address and retrieving the encoded slices in accordance withthe retrieval method based on the DSN address. In other words, the settop box can determine the list of media content it has recorded.

In another example of retrieval, the set top box retrieves media contentthat the set top box did not previously store in a distributed fashion(e.g., but at least one other of the set top boxes invoked storing thecontent element) based on translating a media content ID (or accessing aDSN directory of another set top box) into a virtual DSN address andretrieving the encoded data slices in accordance with the retrievalmethod based on the DSN address. In other words, the DS processingmodule of the set top box can determine the list of media content thatother set top boxes (e.g., in the same social group as the set top box)have recorded. In this example, set top boxes may share their DSNdirectories.

In another example of retrieval, a method begins with the DS processingmodule selecting media content to retrieve and obtaining social mediametadata regarding the media content. The social media metadata mayinclude one or more of but not limited to a media selection list, asocial network member list, a stored media content list, and adispersed-storage-address-to-memory-location table. The DS processingmodule may obtain the social media metadata by one or more of receivingthe social media metadata from one or more of the other set top boxes inresponse to a request, receiving the social media metadata from thecable head end, receiving the social media metadata from a DS managingunit, and retrieving the social media metadata from a memory 254 of theset top box.

The method continues with the DS processing module retrieving aplurality of sets of encoded data slices from a plurality of memoriesbased on the social media metadata. Note that the social media metadatamay indicate which memories contain the encoded data slices. Theplurality of memories comprises one or more of but not limited to amemory associated with the distributed storage processing module, amemory within a member of the local storage network, and a memory of adispersed storage network.

The method continues with the DS processing module re-creating the mediacontent from the plurality of sets of encoded data slices in accordancewith an error coding dispersal storage function. The DS processingmodule determines members of the social network to receive thereconstructed media content to produce identified members. The DSprocessing module sends the reconstructed media content to theidentified members. Alternatively, the DS processing module encrypts themedia content and/or compresses the media content prior to transmittingthe reconstructed media content. In another alternative, the DSprocessing module determines a display protocol for each of theidentified members and converts a format of the reconstructed mediacontent in accordance with the display protocol of one of the identifiedmembers. In other words, the DS processing module converts thereconstructed media content into a format compatible with the identifiedmembers.

FIG. 17 is a schematic block diagram of an embodiment of a distributedstorage system utilizing a routing storage layer 270 to supplement theDSN memory 22 (e.g., a DS processing unit 14 may store slices in therouting storage layer 270 and/or a DSN memory 22) as described in moredetail with reference to FIGS. 17-21.

As illustrated, the system includes the DS processing unit 14, therouting storage layer 270, and the DSN memory 22. The DSN memory 22includes a plurality of DS units 1-n. The routing storage layer 270includes a plurality of routers that function to operably couple the DSprocessing unit 14 and the DSN memory 22 as well as to store encodeddata slices. For example, the routing storage layer 270 includes routers1-5 that operably couple the DS processing unit 14 to the DSN memory 22.Note that the routing storage layer 270 may include at least a portionof the network.

Router 1, which is representative of the other routers, includes a DSprocessing 34, a slice memory 262, a routing engine 264, a routing table266, and a router interface 268. The router may be fixed or portable andimplemented utilizing the computer core of FIG. 2. The router interface268 couples other system elements to the router to receive and transmitdata packets and may be wire lined or wireless and may couple to anynumber of other routers or system elements. The routing engine 264receives data packets via the router interface 268, processes thereceived data packets, communicates with the DS processing 34, utilizesthe routing table 266, forms transmit data packets to be transmitted,and transmits the transmit data packets via the router interface 268.

The router receives data packets from one system element and forwardsthe data packets to another system element. For example, router 1receives data packets targeting DS unit 1 from the DS processing unit 14and forwards the data packets to the DS unit 1 through router 4.Alternatively, or in addition, the router may receive data packets fromone system element and forward the data packets through multiple otherrouters to another system element. For example, router 1 receives datapackets targeting DS unit 2 from the DS processing unit 14 and forwardsthe data packets through router 4, through router 3, through router 2,and through router 5 to the DS unit 2. The routing engine 264 determineshow the router will process the received data packet, where the routerwill send the transmit data packets (e.g., the destination), and whatroute (e.g., path) will be utilized.

The routing engine 264 determines the connections between routers andpopulates the routing table 266 with entries to signify the connectionsbetween routers. The determination may be based on one or more of apredetermination, a command, and/or discovery. In addition, the routingengine 264 performs the discovery by sending discovery messages via therouter interface 268 and receiving responses via the router interface268 noting which portion of the router interface 268 received whichmessages. The discovery message may include a router ID, a discoverycommand, and a performance indicator. Further, the routing engine 264updates the routing table contents from time to time as system topologydynamically changes. An example of a populated routing table isdiscussed in greater detail with reference to FIG. 18.

The routing engine 264 determines where to forward the slices within thedispersed storage network using one or more methods previously discussedwith reference to FIGS. 10-13 based on the routing table 266. Forexample, the routing engine 264 chooses to forward slices down the pathof router 2 to router 3 to router 4 based on the routing table 266indicating those routers are linked in that order. Note that the systembenefit may be less network traffic.

The router DS processing 34 creates error coded data slices from data orrecreates data from slices less supporting the distributed storagemethods previously discussed with reference to FIGS. 14-15. The DSprocessing 34 stores error coded data slices in the slice memory 262 ofthe router or in the slice memory 262 of other routers. For example,router 1 creates and sends slices to routers 3 and 5 based on receivinga slice from the DS processing unit 14 to further slice and store. Notethat, in this fashion, the router may function as a DS unit.

The DS processing unit 14 determines routers to store and retrieveslices in accordance with a distributed storage method previouslydiscussed with reference to FIGS. 6-15 and based in part on the routingtable 266. For example, the DS processing unit 14 determines to storeslices in router 1 since the routing table 266 reveals that router 1 isconnected directly to the DS processing unit 14 and fast performance isfavored. In another example, the DS processing unit 14 determines tostore slices in router 3 since the routing table 266 reveals that thereare at least four routes between router 3 and the DS processing unit 14and connection reliability is favored over fast performance. The DSprocessing unit 14 method of determining routers is discussed in greaterdetail with reference to FIGS. 18-19.

In an example, the router DS processing 34 determines to affiliate withone or more DS units in the DSN memory 22 or within another router toproduce an affiliation. The determination may be based on one or more ofa router status indicator, a command, the routing table 266, andmetadata associate with the error coded data slice. The routing engine264 subsequently determines how to route and potentially store data inthe router slice memory 262 as slices based in part on the affiliation(e.g., store in the slice memory 262 in place of or in addition to theDS unit). For example, the router 4 DS processing 34 determines toaffiliate with DS unit 1 due to the direct connection. The router 5 DSprocessing 34 determines to affiliate with DS unit 2 due to the directconnection. As a more specific example, the router 5 routing engine 264determines to temporarily store error coded data slices intended for DSunit 2 in the router 5 slice memory 262. The router DS processing methodof determining and utilizing DS unit affiliation is discussed in greaterdetail with reference to FIGS. 20-21.

FIG. 18 is an example table representing a routing table 266 for thetopology of the example depicted with reference to FIG. 17. The routingtable 266 includes entries for source identifiers (ID) of source nodes,destination identifiers (ID) for destination nodes, a route ID, a routepriority, and a route. The route ID signifies a unique route between,from and to nodes through the nodes listed in the route field, which aredetermined by the routing engine as previously discussed (e.g., viasending and receiving discovery messages). Each route permutation islisted as a unique route. The route priority field signifies a rating ofthe associated route. The route signifies the system nodes along a pathfrom the source node to the destination node.

The routing engine determines the route priority in a step subsequent todiscovering possible routes by rating the permutations of routes sharingthe same from and to nodes with respect to each other. The example inFIG. 18 indicates one such rating scheme based on estimated latencyperformance (e.g., to minimize time delays through the routing storagelayer by minimizing the hops through different nodes). For example,route 3 of the DSPU to DS unit 1 route has a route priority of 1 sinceit has the fewest number of nodes along the route as compared to routes1 and 2 and hence has the lowest estimated latency.

Alternatively, the routing engine determines more entry columns todepict other facets including the estimated or measured performance ofthe links between the nodes to enable further refinement of performancebased decisions. Note that the performance entry may depict latency,speed, capacity, error rates, etc.

Alternatively, additional entries may be added to the routing table 266to depict all the routes between every two elements and nodes of thesystem. The routing table 266 may be utilized in part by the DSprocessing unit, router DS processing, and/or the routing engine todetermine how to route data packets, where to store slices, where toretrieve slices, where to forward slices, and how to establishaffiliations. The methods to utilize the routing table 266 methods willbe discussed in greater detail with reference to FIGS. 19-21.

FIG. 19 is a flowchart illustrating the determination of routers where aDS processing module determines which router to send error coded dataslices to for storage or for forwarding to another router based in parton the routing table. The DS processing may be implemented in aprocessing module of a router, a user device, a DS processing unit, a DSmanaging unit, a storage integrity processing unit, and/or a DS unit.For example, the processing module performing the DS processing functionis implemented in the router.

The method begins at step 272 where the processing module receives datafor storage. The processing module may receive the data from a sourceassociated with a source identifier (ID) or from another router. Inaddition, the processing module may receive a user ID, a data objectname, and metadata associated with the data. The method continues atstep 274 where the processing module determines metadata, which includesone or more of but not limited to a hash of the data, a priorityrequirement, a security requirement, a performance requirement, a sizeindicator, a data type indicator, a location requirement, and a user ID.The determination may be based on one or more of the received metadata,the user ID, the data object name, a data type indicator, the dataobject, a calculated hash of the data object, a priority indicator, asecurity indicator, a performance requirement, a command, a user vaultlookup, geographic location of the user device, a location requirement,and a predetermination.

The processing module interprets the data to determine whether the datais to be forwarded or error encoded. The interpretation may be based onone or more of but not limited to the data, the metadata, a command, apredetermination, a lookup, and a message. When the data is to beencoded, the processing module encodes the data using an error codingdispersal storage function to produce error encoded data (e.g. aplurality of sets of encoded data slices). The processing module thendetermines whether to forward the data or error encoded data to localmemory or to another router. The determination is based on one or moreof but not limited to a memory status indicator, the data, the metadata,a command, a predetermination, a lookup, and a message. For example, theprocessing module determines to utilize the local memory when memorystatus indicator indicates favorable memory capacity. The processingmodule outputs the data to the local memory when the data is to beforwarded to the local memory. Alternatively, the processing moduleoutputs the data to the other router when the data is to be forwarded tothe other router.

When data is to be forwarded to another router, the method continues atstep 276 where the processing module determines the routing table. Thedetermination may be based on one or more of but not limited to a sourceidentifier (ID) associated with the data, a destination identifier (ID)associated with the data, and information regarding a plurality ofrouting options. The processing module may obtain the routing tablethrough at least one of receiving the routing table in response to arequest message, retrieving the routing table from a routing tabledatabase, receiving the routing table in conjunction with receiving thedata, and receiving metadata associated with the data and utilizing themetadata to obtain the routing table.

The method continues at step 278 where the processing module determinestarget router (or routers for a storage set) by selecting a routingoption from the plurality of routing options. The processing moduleselects the routing option based on one or more of but not limited tothe metadata, requirements indicated by a router status indicator, arouter performance history indicator, a router attributes list (e.g.,maximum memory), an available router memory indicator, a maximum numberof routes from the DS processing unit to the candidate storage node(router), a minimum number of nodes along the route from the DSprocessing unit to the candidate storage node, a source associated withthe source ID, a destination associated with the destination ID, routingperformance information, a routing preference (e.g., from the routerperspective), and a routing requirement (e.g., from the sourceperspective). For example, the processing module determines to targetrouter 2 since it has enough memory and is just one node away from theDS processing unit. In another example, the processing module determinesto target router 5 since it has enough memory and is just two nodes awayfrom the DS processing unit when router 2 did not have enough memory.Note that the processing module may or may not save which router waschosen based on the distributed storage method as previously discussed.

The method continues at step 280 where the processing module determineserror coding dispersal storage function parameters based on the routingoption. The determination is based on one or more of but not limited tothe target router(s), the metadata, a capability indicator of the targetrouter(s), a command, a predetermination, and a user vault lookup. Inthis step, the processing module may save the parameters in a uservault, in the metadata, and/or another memory and may or may not savethe target router choices (e.g., per slice name and/or data segment ID)in the user vault, a virtual DSN address (e.g., slice name) to physicallocation table, and/or another memory. In an alternative, the processingmodule performs subsequent error coded data slice retrievals throughanother method when the processing module does not save the targetrouter choices. In another alternative, the processing module performssubsequent error coded data slice retrievals by looking up in memorywhere the slices are stored when the processing module saves the targetrouter choices.

The method continues at step 282 where the processing module encodes thedata based on the error coding dispersal storage function parameters toproduce a plurality of sets of encoded data slices. Note that a set ofthe encoded data slices may pertain to error coded data slices of eachpillar of one data segment. The plurality of sets of encoded data slicesmay pertain to the error coded data slices of all the data segments ofthe data. In addition, the processing module unit may append themetadata to the error coded data slices and send the slices (e.g., tothe target routers with a store command for subsequent storage in thetarget routers). Note that the processing module may send one slice, allthe slices batched for a pillar of a data segment, all the slices of adata segment, or all the slices of all the data segments of the dataobject. The method may branch back to the step where the processingmodule determines the target router(s) when the DS processing unit isnot finished creating and sending slices for the data. For example, thesteps described above may repeat for the next data segment.

At step 282, the processing module determines whether one of theplurality of pillars of encoded data slices is to be stored locally asdiscussed previously. The processing module outputs the one of theplurality of pillars of encoded data slices to a local memory when theone of the plurality of pillars of encoded data slices is to be storedlocally.

Continuing at step 282, the processing module outputs at least some ofthe encoded data slices of a set of the plurality of sets of encodeddata slices to an entry point of the routing option. Note that the entrypoint may be another router where the data is subsequently sent to otherrouters for forwarding or error encoding and distributed storage. Notethat the processing module partitions the plurality of sets of encodeddata slices into a plurality of pillars of encoded data slices,determining destinations for each of the plurality of pillars of encodeddata slices in accordance with the destination ID, and outputting theplurality of pillars of encoded data slices to the destinations.

Alternatively, the processing module sends at least a write threshold ofone set of the plurality of sets of encoded data slices to the top ratedrouters for storage. The write threshold may be the minimum number ofpillars allowed to successfully store to in accordance with theoperational parameters. Note that the write threshold is equal to orgreater than the read threshold k and less than or equal to the pillarwidth n. The processing module may send any remaining pillars of errorcoded data slices beyond the write threshold number to routers with arating that is equal to or less than the rating of the top rated routersfor storage.

FIG. 20 is a flowchart illustrating the affiliation determination of arouter where the router utilizes the routing table to affiliate with aDS unit. The method may be implemented in a processing module of arouter, a user device, a DS processing unit, a DS managing unit, astorage integrity processing unit, and/or a DS unit. For example, theprocessing module is implemented in the router.

The method begins at step 284 where the processing module determines therouting table. The determination may be based on one or more of but notlimited to querying the routing table, querying the routing engine, andperforming the discovery method previously described (e.g., theprocessing module of the router pings other routers).

The method continues at step 286 where the processing module determinesan affiliation based on one or more of but not limited to the routingtable, a DS unit status indicator, metadata of a storage sequence,requirements indicated by a router status indicator, a routerperformance history indicator, a router attributes list (e.g., maximummemory), an available router memory indicator, a maximum number ofroutes from the router to the candidate DS unit, a minimum number ofnodes along the route from the router to the candidate DS unit, and aprevious or present router affiliation with a DS unit. For example, therouter 4 processing module may determine to affiliate with DS unit 1since the DS unit 1 status indicator indicates it is busy and/or needshelp, and is just one node away from the router 4 DS processing.

The method continues at step 288 where the processing module sends anaffiliation request message to the DS unit that an affiliation becreated. Next, at step 290 the processing module receives an affiliationrequest response message that may indicate if the DS unit agrees to theaffiliation with a response (e.g., yes or no). The DS unit determineswhether the DS unit requires the help or not. For example, if the DSunit is temporarily falling behind in DS unit activities, it may agreeto the affiliation.

The method continues at step 292 where the processing module determineswhether the affiliation request response message is favorable (e.g.,favorable=yes and/or agree). The method branches back to step 284 whenthe processing module determines that the affiliation request responsemessage is not favorable. The method continues to step 294 when theprocessing module determines that the affiliation request responsemessage is favorable. At step 294 where the processing module saves theaffiliation to the DS unit in one or more of the routing table, a slicememory, and DSN memory when the processing module determines that theaffiliation request response message is favorable.

FIG. 21 is a flowchart illustrating the routing of data where the routerdetermines how to route traffic and/or store slices based in part on anaffiliation to a DS unit. The method may be implemented in a processingmodule of a router, a user device, a DS processing unit, a DS managingunit, a storage integrity processing unit, and/or a DS unit. Forexample, the processing module is implemented in the router.

The method begins at step 296 where the processing module receives adata packet. The data packet includes an encoded data slice of a set ofencoded data slices, wherein a data segment is encoded using an errorcoding dispersal storage function to produce the set of encoded dataslices. At step 298, the processing module inspects the data packet(e.g., opens the packets to find control, payload and routinginformation such as the destination node, next node) to determine adestination of the data packet. The destination may include a dispersedstorage unit of a dispersed storage network.

The method continues at step 300 where the processing module determineswhether the router has an affiliation with the destination. Thedetermination is based on one or more of but not limited to accessing arouter table database and receiving metadata (e.g., the metadataindicates the affiliation). In addition, the processing module maydetermine whether another router does not have an active affiliationwith the destination. Note that the processing module indicates that therouter does not have the affiliation and forwards the data packet to theother router when the other router does have the active affiliation.Alternatively, the processing module determines to establish an activeaffiliation with the destination when the other router does not have theactive affiliation. The processing module determines the activeaffiliation based on one or more of but not limited to a destinationperformance indicator, a maximum number of routes, a minimum number ofroutes, and an affiliation history record.

The method continues at step 302 where the processing module determinestarget DS unit based in part on the data packet (e.g., the destinationnode). For example, the DS unit ID and/or internet protocol address maybe contained in the data packet. The method continues at step 304 wherethe processing module determines whether the router is affiliated withthe target DS unit based on comparing the retrieved affiliation with thetarget DS unit. Note that a match indicates the router is affiliatedwith the target DS unit.

The method continues at step 306, the processing module sends thereceived data packets to the next node (e.g., from the inspectioninformation, a header, a determination by the routing engine based onthe destination node and the routing table) when the routing enginedetermines that the router is not affiliated with the target DS unit.The method continues to step 308 when the processing module determinesthat the router is affiliated to the destination target.

At step 308, the processing module determines whether to temporarilylocally store the data packet. The determination is based on at leastone of interpreting metadata associated with the data packet,interpreting historical data traffic of the destination, interpretingcurrent data traffic of the destination, and receiving a request fromthe destination. For example, the processing module determines totemporarily locally store the data packet when an indication of currentdata traffic of the destination indicates that the data traffic is veryhigh. In addition, the processing module locally stores the data packet(e.g. caches) in the router slice. Note that the router may store theslices for a temporary or long term period.

The method continues at step 310 where the processing module determinesa transfer protocol. The transfer protocol may include one or more ofbut not limited to forwarding the data packet at expiration of a timeinterval, forwarding the data packet during a given time of the day,forwarding the data packet in response to a request from thedestination, forwarding the data packet when a local memory utilizationis above a threshold, forwarding the data packet in response to a changein routing table information, and forwarding the data packet in responseto a change in the affiliation. The determination of the transferprotocol may be based on one or more of but not limited to the routingtable, a DS unit status indicator, the metadata of the slices,requirements indicated by a router status indicator, a routerperformance history indicator, a router attributes list (e.g., maximummemory), an available router memory indicator, a maximum number ofroutes from the router to the candidate DS unit, a minimum number ofnodes along the route from the router to the candidate DS unit, and aprevious or present router affiliation with a DS unit.

The method continues at step 312 where the processing module forwardsthe data packet to the destination in accordance with the transferprotocol. In addition the processing module may respond to a writerequest associated with the data packet, wherein the write request mayinclude one of a write request message, a commit request message, and afinalize request message. For example, the processing module sends awrite request acknowledgment message to the DS processing unit inresponse to receiving the write request message. In another example, theprocessing module sends a commit acknowledgment message to the DSprocessing unit in response to receiving the commit request message. Inanother example, the processing module sends a finalize acknowledgmentthe message to the DS processing unit in response to receiving thefinalize request message. In addition, the processing module determineswhether the error coded data slices are stored in the local memory firstupon subsequent retrieval sequences before forwarding an associatedretrieval command to the affiliated DS unit (e.g., when the slices arenot cached in the router).

As may be used herein, the terms “substantially” and “approximately”provides an industry-accepted tolerance for its corresponding termand/or relativity between items. Such an industry-accepted toleranceranges from less than one percent to fifty percent and corresponds to,but is not limited to, component values, integrated circuit processvariations, temperature variations, rise and fall times, and/or thermalnoise. Such relativity between items ranges from a difference of a fewpercent to magnitude differences. As may also be used herein, theterm(s) “coupled to” and/or “coupling” and/or includes direct couplingbetween items and/or indirect coupling between items via an interveningitem (e.g., an item includes, but is not limited to, a component, anelement, a circuit, and/or a module) where, for indirect coupling, theintervening item does not modify the information of a signal but mayadjust its current level, voltage level, and/or power level. As mayfurther be used herein, inferred coupling (i.e., where one element iscoupled to another element by inference) includes direct and indirectcoupling between two items in the same manner as “coupled to”. As mayeven further be used herein, the term “operable to” indicates that anitem includes one or more of power connections, input(s), output(s),etc., to perform one or more its corresponding functions and may furtherinclude inferred coupling to one or more other items. As may stillfurther be used herein, the term “associated with”, includes directand/or indirect coupling of separate items and/or one item beingembedded within another item. As may be used herein, the term “comparesfavorably”, indicates that a comparison between two or more items,signals, etc., provides a desired relationship. For example, when thedesired relationship is that signal 1 has a greater magnitude thansignal 2, a favorable comparison may be achieved when the magnitude ofsignal 1 is greater than that of signal 2 or when the magnitude ofsignal 2 is less than that of signal 1.

The present invention has also been described above with the aid ofmethod steps illustrating the performance of specified functions andrelationships thereof. The boundaries and sequence of these functionalbuilding blocks and method steps have been arbitrarily defined hereinfor convenience of description. Alternate boundaries and sequences canbe defined so long as the specified functions and relationships areappropriately performed. Any such alternate boundaries or sequences arethus within the scope and spirit of the claimed invention.

The present invention has been described above with the aid offunctional building blocks illustrating the performance of certainsignificant functions. The boundaries of these functional buildingblocks have been arbitrarily defined for convenience of description.Alternate boundaries could be defined as long as the certain significantfunctions are appropriately performed. Similarly, flow diagram blocksmay also have been arbitrarily defined herein to illustrate certainsignificant functionality. To the extent used, the flow diagram blockboundaries and sequence could have been defined otherwise and stillperform the certain significant functionality. Such alternatedefinitions of both functional building blocks and flow diagram blocksand sequences are thus within the scope and spirit of the claimedinvention. One of average skill in the art will also recognize that thefunctional building blocks, and other illustrative blocks, modules andcomponents herein, can be implemented as illustrated or by discretecomponents, application specific integrated circuits, processorsexecuting appropriate software and the like or any combination thereof.

1. A method for execution by a dispersed storage processing module, themethod comprises: obtaining data for storage; encoding the data inaccordance with an error coding dispersal storage function to produce aplurality of sets of encoded data slices; determining a proxy unit; andtransmitting the plurality of sets of encoded data slices to the proxyunit, wherein the proxy unit disperses the plurality of sets of encodeddata slices to a plurality of dispersed storage (DS) units.
 2. Themethod of claim 1 further comprises: transmitting metadata to the proxyunit, wherein the metadata includes a dispersal approach regarding howthe proxy unit is to disperse the plurality of sets of encoded dataslices.
 3. The method of claim 2, wherein the dispersal approach furthercomprises at least one of: disperse in a sequential fashion; disperse ina daisy chain fashion; disperse in a one-to-many fashion; and forward toa second proxy unit, wherein the second proxy unit disperses theplurality of sets of encoded data slices to the plurality of dispersedstorage units.
 4. The method of claim 1 further comprises: receivingdispersed storage information regarding dispersed storage of theplurality of sets of encoded data slices, wherein the dispersed storageinformation includes one or more of: an encoded data slice storageconfirmation identifier; a DS unit identifier and at least oneassociated slice name; a seed DS unit identifier; an end DS unitidentifier; and storage path information.
 5. The method of claim 1,wherein the determining the proxy unit further comprises: selecting oneof the plurality of dispersed storage units.
 6. A method for executionby a dispersed storage (DS) unit, the method comprises: receiving aplurality of sets of encoded data slices; receiving metadata associatedwith the plurality of sets of encoded data slices; interpreting themetadata to determine storage instructions regarding the plurality ofencoded data slices; and when the storage instructions indicate daisychain storage: locally storing first encoded data slices of each set ofencoded data slices; and forwarding other encoded data slices of thesets of encoded data slices to at least one other DS unit.
 7. The methodof claim 6 further comprises: when the storage instructions indicate thedaisy chain storage: updating the metadata to produce updated metadata;locally storing the updated metadata; and forwarding the updatedmetadata to the at least one other DS unit.
 8. The method of claim 6further comprises: when the storage instructions indicate the daisychain storage: updating the metadata to produce updated metadata;determining whether the DS unit is an end DS unit; and when the DS unitis the end DS unit, forwarding the updated metadata to a DS processingmodule.
 9. The method of claim 6 further comprises: when the storageinstructions indicate one-to-many storage: transmitting pillar numberedencoded data slices of the plurality of sets of encoded data slices tocorresponding ones of a plurality of DS units, wherein the plurality ofDS units includes the at least one other DS unit.
 10. The method ofclaim 6 further comprises: receiving a retrieval message from aninitiator; retrieving locally stored metadata in response to theretrieval message; retrieving stored encoded data slices in accordancewith the locally stored metadata; sending the stored encoded data slicesto the initiator; and forwarding the retrieval message to the at leastone other DS unit in accordance with the locally stored metadata.
 11. Adispersed storage processing module comprises: an interface; and aprocessing module operable to: obtain data for storage; encode the datain accordance with an error coding dispersal storage function to producea plurality of sets of encoded data slices; determine a proxy unit; andtransmit, via the interface, the plurality of sets of encoded dataslices to the proxy unit, wherein the proxy unit disperses the pluralityof sets of encoded data slices to a plurality of dispersed storage (DS)units.
 12. The dispersed storage processing module of claim 11, whereinthe processing module further functions to: transmit, via the interface,metadata to the proxy unit, wherein the metadata includes a dispersalapproach regarding how the proxy unit is to disperse the plurality ofsets of encoded data slices.
 13. The dispersed storage processing moduleof claim 12, wherein the dispersal approach further comprises at leastone of: disperse in a sequential fashion; disperse in a daisy chainfashion; disperse in a one-to-many fashion; and forward to a secondproxy unit, wherein the second proxy unit disperses the plurality ofsets of encoded data slices to the plurality of dispersed storage units.14. The dispersed storage processing module of claim 11, wherein theprocessing module further functions to: receive, via the interface,dispersed storage information regarding dispersed storage of theplurality of sets of encoded data slices, wherein the dispersed storageinformation includes one or more of: an encoded data slice storageconfirmation identifier; a DS unit identifier and at least oneassociated slice name; a seed DS unit identifier; an end DS unitidentifier; and storage path information.
 15. The dispersed storageprocessing module of claim 11, wherein the processing module furtherfunctions to determine the proxy unit by: selecting one of the pluralityof dispersed storage units.
 16. A dispersed storage (DS) unit comprises:an interface; a memory; and a processing module operable to: receive,via the interface, a plurality of sets of encoded data slices; receive,via the interface, metadata associated with the plurality of sets ofencoded data slices; interpret the metadata to determine storageinstructions regarding the plurality of encoded data slices; and whenthe storage instructions indicate daisy chain storage: locally store, inthe memory, first encoded data slices of each set of encoded dataslices; and forward, via the interface, other encoded data slices of thesets of encoded data slices to at least one other DS unit.
 17. Thedispersed storage unit of claim 16, wherein the processing modulefurther functions to: when the storage instructions indicate the daisychain storage: update the metadata to produce updated metadata; locallystore, in the memory, the updated metadata; and forward, via theinterface, the updated metadata to the at least one other DS unit. 18.The dispersed storage unit of claim 16, wherein the processing modulefurther functions to: when the storage instructions indicate the daisychain storage: update the metadata to produce updated metadata;determine whether the DS unit is an end DS unit; and forward, via theinterface, the updated metadata to a DS processing module, when the DSunit is the end DS unit.
 19. The dispersed storage unit of claim 16,wherein the processing module further functions to: when the storageinstructions indicate one-to-many storage: transmit, via the interface,pillar numbered encoded data slices of the plurality of sets of encodeddata slices to corresponding ones of a plurality of DS units, whereinthe plurality of DS units includes the at least one other DS unit. 20.The dispersed storage unit of claim 16, wherein the processing modulefurther functions to: receive, via the interface, a retrieval messagefrom an initiator; retrieve, from the memory, locally stored metadata inresponse to the retrieval message; retrieve, from the memory, storedencoded data slices in accordance with the locally stored metadata;send, via the interface, the stored encoded data slices to theinitiator; and forward, via the interface, the retrieval message to theat least one other DS unit in accordance with the locally storedmetadata.